Premium
An unconventional IAP‐binding motif revealed by target‐assisted iterative screening (TAIS) of the BIR3‐cIAP1 domain
Author(s) -
Kurakin Alexei,
Bredesen Dale E.
Publication year - 2006
Publication title -
journal of molecular recognition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.401
H-Index - 79
eISSN - 1099-1352
pISSN - 0952-3499
DOI - 10.1002/jmr.809
Subject(s) - peptide , peptide library , motif (music) , alanine scanning , tryptophan , computational biology , chemistry , binding site , phage display , plasma protein binding , biology , peptide sequence , microbiology and biotechnology , biochemistry , biophysics , amino acid , physics , gene , mutant , mutagenesis , acoustics
Target‐assisted iterative screening (TAIS) has been applied to a random phage‐displayed peptide library in a search for novel ligands of the third b aculovirus I AP (‘inhibitors of apoptosis’) r epeat (BIR) domain of cIAP1. The peptides selected in the screen fall into two distinct specificity groups, one that conforms to a known IAP‐binding motif (IBM) and another one that reveals a novel BIR domain interacting motif, NH 2 ‐SR(V/P)W. The biochemical profiling of selected sequences with synthetic peptides, which included alanine scanning and N‐ and C‐terminal truncations as well as competition with the Smac peptide, suggests a major energetic contribution of tryptophan at the +4 position of peptide ligands to binding and identifies the latter together with the respective pocket on the BIR domain surface as a ‘hot spot’ of the interaction. A peptide featuring the novel motif selectively binds the full‐length cIAP1 protein in cell lysates. A ‘two‐pocket’ model of BIR domain recognition mechanism is proposed as the basis of differential BIR domain interactions with different IBMs. Copyright © 2006 John Wiley & Sons, Ltd.