title: Multibranch and pseudopeptide approach for design of novel inhibitors of subtilisin kexin isozyme-1.
abstract: Here we developed small molecule inhibitors of SKI-1/S1P enzyme of the Proprotein Convertase family following two approaches. One involves the assembly of multi-branch peptides while the other utilizes the insertion of alkyloxy pseudo peptide bond at P1-P1' cleavage position. In first approach, 2 and 4-branch peptides were designed based on the human (h) SKI-1(128-137) sequence, located N-terminal to its secondary activation site (K(137) downward arrow L). The 4-branch peptide exhibited the highest SKI-1 inhibitory property (IC(50) = 0.9 microM) with approximately 8.6 and 1.3-fold more potency than the corresponding single and 2-branch peptides, respectively. In the second strategy, an oxymethylene containing unnatural amino acid such as aminooxy-acetic acid (Aoaa) or 8-amino-3, 6 dioxa-octanoic acid (Adoa) was introduced substituting P1, P1' or both residues of hSKI-1(183-190) and hSKI-1(178-190) segments. These domains contain the same primary hSKI-1 activation site L(186) downward arrow R. Among those tested, P7-Tyr mutant [(178)GRYSSRRL(Adoa)AIP(190)] exhibited higher SKI-1 inhibitory activity (K(i)in low microM). Circular dichroism (CD) spectra of SKI-1 inhibitors showed interactions of varying degrees between the enzyme and the inhibitor consistent with the observed inhibition profile. A 3D-homology model structure of SKI-1 catalytic domain indicated a broad catalytic pocket.
authors.affiliation: Regional Protein Chemistry Center, Diseases of Aging Program, Ottawa Health Research Institute, 725 Parkdale Ave, Ottawa, ON, Canada.
authors.forename: Sarmistha
authors.initials: S
authors.lastname: Basak
authors.forename: Dayani
authors.initials: D
authors.lastname: Mohottalage
authors.forename: Ajoy
authors.initials: A
authors.lastname: Basak
mesh_terms: D000595:Amino Acid Sequence; D020134:Catalytic Domain; D002942:Circular Dichroism; D006801:Humans; D006860:Hydrogen Bonding; D007527:Isoenzymes / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D043484:Proprotein Convertases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D010455:Peptides; D011994:Recombinant Proteins; D043484:Proprotein Convertases; D012697:Serine Endopeptidases; C115575:membrane-bound transcription factor peptidase, site 1