Patent Application
20180179252
The present invention is concerned with peptides having dual BACE1 inhibitory properties, their manufacture, pharmaceutical compositions containing them and their use as therapeutically active substances.
The present compounds have Asp2 (β-secretase, BACE1 or Memapsin-2) inhibitory activity and may therefore be used in the therapeutic and/or prophylactic treatment of diseases and disorders characterized by elevated β-amyloid levels and/or β-amyloid oligomers and/or β-amyloid plaques and further deposits, particularly Alzheimer's disease.
Alzheimer's disease (AD) is a neurodegenerative disorder of the central nervous system and the leading cause of a progressive dementia in the elderly population. Its clinical symptoms are impairment of memory, cognition, temporal and local orientation, judgment and reasoning but also severe emotional disturbances. There are currently no treatments available which can prevent the disease or its progression or stably reverse its clinical symptoms. AD has become a major health problem in all societies with high life expectancies and also a significant economic burden for their health systems.
The BACE1 enzyme is responsible for one of the proteolytic cleavages of the APP protein that contributes to the generation of the Alzheimer's disease-associated Aβ-peptide. Retarding or stopping the production of Aβ-peptide through inhibition of the BACE1 enzyme is a promising therapeutic concept.
Active site-directed BACE1 inhibitors are described in e.g. WO2006/002907 and exosite-directed (catalytic domain) BACE1 inhibitors are described in e.g. Kornacker et al., Biochemistry 2005, 44, 11567-73. Further Linning, Organic & Biomolecular Chemistry 10(41), 2012, p8216, WO2005097199, US2007149763 and WO2013056054 describe Bacel inhibitors with peptidic structures.
Object of the present invention is dual-site BACE1 inhibitor, binding to both, the enzymatic active site and the catalytic domain of the BACE enzyme, the preparation of the above mentioned compounds, medicaments containing them and their manufacture as well as the use of the above mentioned compounds in the therapeutic and/or prophylactic treatment of diseases and disorders which are associated with inhibition of BACE1 activity, such as Alzheimer's disease. Furthermore, the formation, or formation and deposition, of β-amyloid plaques in, on or around neurological tissue (e.g., the brain) are inhibited by the present compounds by inhibiting the Aβ production from APP or an APP fragment.
The following definitions of the general terms used in the present description apply irrespectively of whether the terms in question appear alone or in combination with other groups.
Table 2: amino acid abbreviations used herein
The term “Sta” stands for statine, (3S,4S)-4-amino-3-hydroxy-6-methylheptanoic acid (CAS 49642-07-1).
The term “MetSta” stands for (3S,4S)-4-amino-3-hydroxy-6-methylthiohexanoic acid (CAS n/a), (CAS of Fmoc protected: 268542-18-3).
The term “PEG(4)” stands for 15-amino-4,7,10,13,tetraoxapentadecanoic acid (CAS: n/a), (CAS of Fmoc protected: 557756-85-1).
The term Leu*Ala stands for the “Tang” hydroxyethylene dipeptide isostere (reference: A. K.Ghosh, D. Shin, D. Downs, G. Koelsch, X. Lin, J. Ermolieff and J. Tang, J. Am. Chem. Soc., 2000, 122, 3522).
The term “PEG2” stands for 8-amino-3,6-dioxaoctanoic- acid (CAS: n/a), (CAS of Fmoc protected: 166108-71-0)
The term “PEG3” stands for 12-amino-4,7,10-trioxadodecanoic acid (CAS: n/a), CAS of Fmoc protected: 867062-95-1)
The term “pharmaceutically acceptable salts” refers to salts that are suitable for use in contact with the tissues of humans and animals. Examples of suitable salts with inorganic and organic acids are, but are not limited to acetic acid, citric acid, formic acid, fumaric acid, hydrochloric acid, lactic acid, maleic acid, malic acid, methane-sulfonic acid, nitric acid, phosphoric acid, p-toluenesulphonic acid, succinic acid, sulfuric acid, sulphuric acid, tartaric acid, trifluoroacetic acid (TFA) and the like. A specific salt is trifluoroacetate.
The terms “pharmaceutically acceptable carrier” and “pharmaceutically acceptable auxiliary substance” refer to carriers and auxiliary substances such as diluents or excipients that are compatible with the other ingredients of the formulation.
The term “pharmaceutical composition” encompasses a product comprising specified ingredients in pre-determined amounts or proportions, as well as any product that results, directly or indirectly, from combining specified ingredients in specified amounts. Preferably it encompasses a product comprising one or more active ingredients, and an optional carrier comprising inert ingredients, as well as any product that results, directly or indirectly, from combination, complexation or aggregation of any two or more of the ingredients, or from dissociation of one or more of the ingredients, or from other types of reactions or interactions of one or more of the ingredients.
The term “half maximal inhibitory concentration” (IC50) denotes the concentration of a particular compound required for obtaining 50% inhibition of a biological process in vitro. IC50 values can be converted logarithmically to pIC50 values (−log IC50), in which higher values indicate exponentially greater potency. The IC50 value is not an absolute value but depends on experimental conditions e.g. concentrations employed. The IC50 value can be converted to an absolute inhibition constant (Ki) using the Cheng-Prusoff equation (Biochem. Pharmacol. (1973) 22:3099). The term “inhibition constant” (Ki) denotes the absolute binding affinity of a particular inhibitor to a receptor. It is measured using competition binding assays and is equal to the concentration where the particular inhibitor would occupy 50% of the receptors if no competing ligand (e.g. a radioligand) was present. Ki values can be converted logarithmically to pKi values (−log Ki), in which higher values indicate exponentially greater potency.
“Therapeutically effective amount” means an amount of a compound that, when administered to a subject for treating a disease state, is sufficient to effect such treatment for the disease state. The “therapeutically effective amount” will vary depending on the compound, disease state being treated, the severity or the disease treated, the age and relative health of the subject, the route and form of administration, the judgment of the attending medical or veterinary practitioner, and other factors.
The term “as defined herein” and “as described herein” when referring to a variable incorporates by reference the broad definition of the variable as well as preferred, more preferred and most preferred definitions, if any.
The terms “treating”, “contacting” and “reacting” when referring to a chemical reaction means adding or mixing two or more reagents under appropriate conditions to produce the indicated and/or the desired product. It should be appreciated that the reaction which produces the indicated and/or the desired product may not necessarily result directly from the combination of two reagents which were initially added, i.e., there may be one or more intermediates which are produced in the mixture which ultimately leads to the formation of the indicated and/or the desired product.
The invention also provides pharmaceutical compositions, methods of using, and methods of preparing the aforementioned compounds.
All separate embodiments may be combined.
Present invention relates to a dual-site BACE1 inhibitor, binding to both, the enzymatic active site and the catalytic domain of the BACE1 enzyme.
The exosite motifs as well as the active site inhibitors containing statine-type transition state mimetic alone do not show BACE1 inhibition.
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein, binding to both, the enzymatic active site and the catalytic domain of the BACE enzyme, whereby the exosite inhibitory part (A′) is connected to the active-site inhibitory part (B′) of said BACE1 inhibitor by a linker (L′), or a pharmaceutically acceptable salt thereof.
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein, wherein L′ is selected from the group consisting of
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein, wherein A′ is selected from the group consisting of
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein, wherein A′ is selected from the group consisting of
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein, wherein B′ is selected from the group consisting of
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein, selected from the group consisting of
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein, selected from the group consisting of
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein, wherein the pharmaceutically acceptable salt is trifluoroacetate.
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein for use as therapeutically active substance.
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein for the use as inhibitor of BACE1 activity.
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein for the use as therapeutically active substance for the therapeutic and/or prophylactic treatment of diseases and disorders characterized by elevated β-amyloid levels and/or β-amyloid oligomers and/or β-amyloid plaques and further deposits, particularly Alzheimer's disease.
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein for the use as therapeutically active substance for the therapeutic and/or prophylactic treatment of Alzheimer's disease.
A certain embodiment of the invention relates to a pharmaceutical composition comprising a dual-site BACE1 inhibitor as described herein and a pharmaceutically acceptable carrier and/or a pharmaceutically acceptable auxiliary substance.
A certain embodiment of the invention relates to the use of a dual-site BACE1 inhibitor as described herein for the manufacture of a medicament for the use in inhibition of BACE1 activity.
A certain embodiment of the invention relates to the use of a dual-site BACE1 inhibitor as described herein for the manufacture of a medicament for the therapeutic and/or prophylactic treatment of diseases and disorders characterized by elevated β-amyloid levels and/or β-amyloid oligomers and/or β-amyloid plaques and further deposits, particularly Alzheimer's disease.
A certain embodiment of the invention relates to the use of a dual-site BACE1 inhibitor as described herein for the manufacture of a medicament for the therapeutic and/or prophylactic treatment of Alzheimer's disease.
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein for the use in inhibition of BACE1 activity.
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein for the use in the therapeutic and/or prophylactic treatment of diseases and disorders characterized by elevated β-amyloid levels and/or β-amyloid oligomers and/or β-amyloid plaques and further deposits, particularly Alzheimer's disease.
A certain embodiment of the invention relates to a dual-site BACE1 inhibitor as described herein for the use in the therapeutic and/or prophylactic treatment of Alzheimer's disease.
A certain embodiment of the invention relates to a method for the use in inhibition of BACE1 activity, particularly for the therapeutic and/or prophylactic treatment of diseases and disorders characterized by elevated β-amyloid levels and/or β-amyloid oligomers and/or β-amyloid plaques and further deposits, Alzheimer's disease, which method comprises administering dual-site BACE1 inhibitor as described herein to a human being or animal.
Furthermore, the invention includes all optical isomers, i.e. diastereoisomers, diastereomeric mixtures, racemic mixtures, all their corresponding enantiomers and/or tautomers as well as their solvates.
The dual-site BACE1 inhibitors may be prepared as described herein. The starting material is commercially available or may be prepared in accordance with known methods.
The corresponding pharmaceutically acceptable salts with acids can be obtained by standard methods known to the person skilled in the art, e.g. by dissolving the dual-site BACE1 inhibitor in a suitable solvent such as e.g. dioxan or THF and adding an appropriate amount of the corresponding acid. The products can usually be isolated by filtration or by chromatography. The conversion of a dual-site BACE1 inhibitor into a pharmaceutically acceptable salt with a base can be carried out by treatment of such a compound with such a base. One possible method to form such a salt is e.g. by addition of 1/n equivalents of a basic salt such as e.g. M(OH)n, wherein M=metal or ammonium cation and n=number of hydroxide anions, to a solution of the compound in a suitable solvent (e.g. ethanol, ethanol-water mixture, tetrahydrofuran-water mixture) and to remove the solvent by evaporation or lyophilisation.
Insofar as their preparation is not described in the examples, the dual-site BACE1 inhibitors as well as all intermediate products can be prepared according to analogous methods or according to the methods set forth herewithin. Starting materials are commercially available, known in the art or can be prepared by methods known in the art or in analogy thereto.
It will be appreciated that the dual-site BACE1 inhibitors in this invention may be derivatised at functional groups to provide derivatives which are capable of conversion back to the parent compound in vivo.
The dual-site BACE1 inhibitor and their pharmaceutically acceptable salts possess valuable pharmacological properties. It has been found that the compounds of the present invention are associated with inhibition of BACE1 activity. The compounds were investigated in accordance with the test given hereinafter.
Cellular Aβ-Lowering Assay:
Human HEK293 cells which are stably transfected with a vector expressing a cDNA of the human APP wt gene (APP695) were used to assess the potency of the compounds in a cellular assay. The cells were seeded in 96-well microtiter plates in cell culture medium (Iscove, plus 10% (v/v) fetal bovine serum, glutamine, penicillin/streptomycin) to about 80% confluence and the compounds were added at a 10× concentration in 1/10 volume of medium without FCS containing 8% DMSO (final concentration of DMSO was kept at 0.8% v/v). After 18-20 hrs incubation at 37° C. and 5% CO2 in a humidified incubator the culture supernatant was harvested for the determination of Aβ40 concentrations. 96well ELISA plates (e.g., Nunc MaxiSorb) were coated with monoclonal antibody which specifically recognize the C-terminal end of Aβ40 (Brockhaus et al., NeuroReport 9, 1481-1486; 1998). After blocking of non-specific binding sites with e.g. 1% BSA and washing, the culture supernatants were added in suitable dilutions together with a horseradish peroxidase-coupled Aβ detection antibody (e.g., antibody 4G8, Senetek, Maryland Heights, Mo.) and incubated for 5 to 7 hrs. Subsequently the wells of the microtiter plate were washed extensively with Tris-buffered saline containing 0.05% Tween 20 and the assay was developed with tetramethylbenzidine/H2O2 in citric acid buffer. After stopping the reaction with one volume 1 N H2SO4 the reaction was measured in an ELISA reader at 450 nm wavelength. The concentrations of Aβ in the culture supernatants were calculated from a standard curve obtained with known amounts of pure Aβ peptide.
The exosite motifs as well as the active site inhibitors containing statine-type transition state mimetic alone do not show BACE1 inhibition.
The dual-site BACE1 inhibitors and the pharmaceutically acceptable salts can be used as therapeutically active substances, e.g. in the form of pharmaceutical preparations. The pharmaceutical preparations can be administered orally, e.g. in the form of tablets, coated tablets, dragees, hard and soft gelatin capsules, solutions, emulsions or suspensions. The administration can, however, also be effected rectally, e.g. in the form of suppositories, or parenterally, e.g. in the form of injection solutions.
The dual-site BACE1 inhibitors and the pharmaceutically acceptable salts thereof can be processed with pharmaceutically inert, inorganic or organic carriers for the production of pharmaceutical preparations. Lactose, corn starch or derivatives thereof, talc, stearic acids or its salts and the like can be used, for example, as such carriers for tablets, coated tablets, dragees and hard gelatin capsules. Suitable carriers for soft gelatin capsules are, for example, vegetable oils, waxes, fats, semi-solid and liquid polyols and the like. Depending on the nature of the active substance no carriers are however usually required in the case of soft gelatin capsules. Suitable carriers for the production of solutions and syrups are, for example, water, polyols, glycerol, vegetable oil and the like. Suitable carriers for suppositories are, for example, natural or hardened oils, waxes, fats, semi-liquid or liquid polyols and the like.
The pharmaceutical preparations can, moreover, contain pharmaceutically acceptable auxiliary substances such as preservatives, solubilizers, stabilizers, wetting agents, emulsifiers, sweeteners, colorants, flavorants, salts for varying the osmotic pressure, buffers, masking agents or antioxidants. They can also contain still other therapeutically valuable substances.
Medicaments containing a dual-site BACE1 inhibitor or a pharmaceutically acceptable salt thereof and a therapeutically inert carrier are also an object of the present invention, as is a process for their production, which comprises bringing one or more dual-site BACE1 inhibitors and/or pharmaceutically acceptable salts thereof and, if desired, one or more other therapeutically valuable substances into a galenical administration form together with one or more therapeutically inert carriers.
The dosage can vary within wide limits and will, of course, have to be adjusted to the individual requirements in each particular case. In the case of oral administration the dosage for adults can vary from about 0.01 mg to about 1000 mg per day of a dual-site BACE1 inhibitors or of the corresponding amount of a pharmaceutically acceptable salt thereof. The daily dosage may be administered as single dose or in divided doses and, in addition, the upper limit can also be exceeded when this is found to be indicated.
The following examples illustrate the present invention without limiting it, but serve merely as representative thereof. The pharmaceutical preparations conveniently contain about 1-500 mg, preferably 1-100 mg, of a dual-site BACE1 inhibitor. Examples of compositions according to the invention are:
Tablets of the following composition are manufactured in the usual manner:
Capsules of the following composition are manufactured:
The dual-site BACE1 inhibitor, lactose and corn starch are firstly mixed in a mixer and then in a comminuting machine. The mixture is returned to the mixer; the talc is added thereto and mixed thoroughly. The mixture is filled by machine into suitable capsules, e.g. hard gelatin capsules.
Soft Gelatin Capsules of the following composition are manufactured:
The dual-site BACE1 inhibitor is dissolved in a warm melting of the other ingredients and the mixture is filled into soft gelatin capsules of appropriate size. The filled soft gelatin capsules are treated according to the usual procedures.
Suppositories of the following composition are manufactured:
The suppository mass is melted in a glass or steel vessel, mixed thoroughly and cooled to 45° C. Thereupon, the finely powdered dual-site BACE1 inhibitor is added thereto and stirred until it has dispersed completely. The mixture is poured into suppository moulds of suitable size, left to cool; the suppositories are then removed from the moulds and packed individually in wax paper or metal foil.
Injection solutions of the following composition are manufactured:
The dual-site BACE1 inhibitor is dissolved in a mixture of Polyethylene Glycol 400 and water for injection (part). The pH is adjusted to 5.0 by acetic acid. The volume is adjusted to 1.0 ml by addition of the residual amount of water. The solution is filtered, filled into vials using an appropriate overage and sterilized.
Sachets of the following composition are manufactured:
The dual-site BACE1 inhibitor is mixed with lactose, microcrystalline cellulose and sodium carboxymethyl cellulose and granulated with a mixture of polyvinylpyrrolidone in water. The granule is mixed with magnesium stearate and the flavoring additives and filled into sachets.
The following examples are provided for illustration of the invention. They should not be considered as limiting the scope of the invention, but merely as being representative thereof.
General Procedures for the CEM Liberty Microwave Peptide Synthesizer:
0.1 mMol scale:
Deprotection of Fmoc:
The washed and preswelled resin (435 mg, 0.1 mMol, TentaGel S RAM (Load: 0.23mMol/g), (Rapp Polymere, Cat: S30023) was treated with a solution of piperidine 20% in dimethylformamid (DMF) (7.0 mL) under microwave condition at 50° C. for 3 minutes for initial deprotection. The resin was washed with DMF and treated with a solution of piperidine 20% in DMF (7.0 mL) under microwave condition at 75° C. for 5 minutes for deprotection.
Coupling of Amino Acids:
To the washed and preswelled resin was added a solution of amino acid, 0.2M in DMF (2.5 mL, 5.0 eq.) followed by a solution of (1-Cyano-2-ethoxy-2-oxoethylidenaminooxy) dimethylamino-morpholino-carbenium hexafluorophosphate (COMU) 0.5M in DMF (1.0 mL, 5.0 eq.), (CAS: 1075198-30-9, Iris Biotech, Cat: RL-1175.1000) followed by a solution of diisopropylethylamine (DIPEA) 2M in N-Methyl-2-pyrrolidone (NMP) (0.5 mL, 10.0 eq.). This reaction mixture was treated under microwave condition at 75° C. for 5 minutes for coupling.
0.25 mMol scale:
Deprotection of Fmoc:
The washed and preswelled resin (1.09 g, 0.25 mMol, TentaGel S RAM (Load: 0.23 mMol/g), (Rapp Polymere, Cat: S30023) was treated with a solution of piperidine 20% in DMF (10.0 mL) under microwave condition at 50° C. for 3 minutes for initial deprotection. The resin was washed with DMF and treated with a solution of piperidine 20% in DMF (10.0 mL) under microwave condition at 75° C. for 5 minutes for deprotection.
Coupling of amino acids:
To the washed and preswelled resin was added a solution of amino acid, 0.2M in DMF (5.0 mL, 4.0 eq.) followed by a solution of COMU 0.5M in DMF (2.0 mL, 4.0 eq.), (CAS: 1075198-30-9, Iris Biotech, Cat: RL-1175.1000) followed by a solution of DIPEA 2M in NMP (1.0 mL, 8.0 eq.). This reaction mixture was treated under microwave condition at 75° C. for 5 minutes for coupling.
General Procedure for Final Cleavage:
0.1 mMol scale:
The resin was washed with CH2Cl2 and then treated with a solution of trifluoroacetic acid (TFA): triisopropylsilane (TIS):water 95:2.5:2.5 (5 mL) for 30 minutes at room temperature on the shaker. The resin was filtered. The crude peptide was precipitated with Et2O (35 mL). The suspension was centrifuged and the solvent was decanted. The solid was dissolved in acetonitrile and water and freeze-dried to get the crude peptide.
General Procedure for Purification:
The crude product was dissolved in acetonitrile and water (containing 0.1% TFA) and then purified by preparative HPLC. Column YMC-Actus Pro C8, 5 μm, 75×30 mm with a gradient of water (containing 0.1% TFA):acetonitrile 70:30 to 2:98 and with a flow of 30 mL/min.
The examples can be prepared analogous to the general procedures described herein.
BACE1 Binder Discovery Using Comprehensive 5mer Peptide Arrays
Array Design, Synthesis and Background Control: To discover BACE1 binders, an array having 2.47M peptides (representing a comprehensive list of all possible 5-mer peptides, excluding cysteine) was designed. Each 5-mer peptide was synthesized with 3 cycles of linker synthesis in the N-term and C-term. For linker synthesis a mixture including G and S in a 3:1ratio was used. The peptide sequence would be in the following format: ZZZ—5mer—ZZZ, where Z is an amino-acid from a linker mixture. After peptide synthesis, arrays were pre-stained with Cy5-streptavidin for the purpose of QC and background signal measurement in 30 ml of Binding buffer (1% alkali-soluble casein, Novagen, Billerica, USA, cat#70955, 0.05%) Tween 20) containing 333 ng/ml Cy5-streptavidin (Amersham, UK, cat# PA45001) for 1 h. Array were washed in Wash Buffer I (Roche/Nimblegen, Madison, USA) for 30 sec and, briefly, in 0.1 TE buffer. The arrays were dried by a spinning in a microfuge to remove traces of water and scanned using MS200 scanner (Roche/Nimblegen) at 635 nm wavelength and 2 μm resolution. After this step, the arrays were ready for binding to a target protein.
BACE1 biotinylation: BACE1 enzyme (WT1-13-2, 0.7 mg/ml) was labelled with biotin using Pierce EZ-link Micro NHS-PEG4-biotinylation kit, cat#21955. For labelling, 70 μl or 50 μg of BACE1 enzyme was mixed with 2 μl of NHS-biotin solution freshly prepared in water and incubated at RT for 1 h. Excess of free biotin was removed by 2× spin-filtration (1,000 g, 4 min) of the reaction solution using Micro Bio-Spin 30 chromatography column (BioRad, cat 732-6223). The biotinylated BACE1 was stored in aliquots at −20C.
Binding Assay: To ensure data reproducibility 5 μl of biotinylated BACE1 was mixed with 40 μl of Binding Buffer, loaded on array with attached HX1 Mixer and incubated at 4C overnight. After incubation, the mixer was removed and array was washed in Wash Buffer I for 30 sec and, briefly in 0.1 TE buffer. The array was stained at biotinylated BACE1 in 30 ml of Binding buffer with 333 ng/ml streptavidin-Cy5 (Amersham, UK, cat# PA45001) for 1 h and washed as described above. The array was dried by spinning in a microfuge to remove traces of water and the data were acquired using MS200 scanner (Roche/Nimblegen) at 635 nm wavelength and 2 um resolution.
Data analysis and Results: Image analysis and signal extraction performed using NimbleGen DEVA software. The biotin specific fluorescent signal resulting from BACE1 binding was plotted against the background signal collected earlier (see “Array Design, Synthesis and Background Control”) for all 5-mer sequences. 5-mer peptide sequences with highest BACE1 -specific signal and low background have been identified from this analysis and six most common motifs shared by these sequences are listed in the first column of the table below.
BACE1 Binder Optimization Using Extension Peptide Arrays.
Array Design: The motifs identified in 5-mer array experiments are likely to represent only short versions of optimal BACE1 binders. Longer motifs can be found by designing new arrays by extending the core sequences selected from 5-mer arrays by two amino acids from both N- and C-terminus using all 20 natural amino acids shown by X in column 2 of Table 2. Each of the extension libraries includes 160,000 unique peptides synthesized in five replicates. BACE1 binding assay and image processing was performed as described in Example 1.
Data analysis and Results: For each core motif, extended sequences with the highest binding to BACE1 are shown in Table 13 (third column). Extended sequences for ‘YFK’, ‘PYFK’ and ‘YFKP’ motifs (top three rows in Table 13) share the same YPYFKPA sequence suggesting that they represent the same common sequence. Three sequences, DYPKFLP, DYPKFIS, SYPKFID, were selected as ‘PKF’ motif extensions because they had similar binding to BACE1 and diverse amino acid composition at the N- and C-terminus.
BACE1 Binder Optimization Using Double Substitution/Deletion Peptide Arrays.
Array Design: he third round of binder optimization included extension of the sequences identified in the extension array experiments with glycine (G) amino acid to make them 10-mer peptides as shown in Table 13 (forth column) followed by design of double substitution/deletion libraries that include all possible single- and double substitution/deletion variants of the reference sequence. For a 10-mer peptide, the double substitution/deletion library included approximately 16.5 thousand unique peptides. Each peptide was synthesized in replicates of seven.
BACE1 binding assay and image processing for substitution/deletion arrays was performed as described above (BACE1 Binder Discovery Using Comprehensive 5mer Peptide Arrays).
Data analysis and Results: Peptides sequences with the highest binding signal were selected after analysing each peptide library which included the outlier removal and averaging signal for each peptide over the replicates. The selected sequences are shown in Table 13 (last column).
| Number | Date | Country | Kind |
|---|---|---|---|
| 15178162.2 | Jul 2015 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2016/067447 | 7/21/2016 | WO | 00 |
