title: Structure-activity relationships of Bak derived peptides: affinity and specificity modulations by amino acid replacement.
abstract: To study the structure-activity relationships (SAR) and the binding activity of pro-apoptotic Bak BH3 domain, we synthesised several 16mer peptide analogues corresponding to the region (72)-GQVGRQLAIIGDDINR-(87). Using different amino acids varying in length, steric and electronic properties, we investigated the role and the nature of physicochemical parameters of residues Val74, Leu78, Ile81 and Ile85, previously identified to be crucial for interactions. With this aim, we measured the affinity of these peptides on two anti-apoptotic proteins Bcl-x(L) and Bcl-2 by a polarization fluorescence competitive assay. We defined that the most potent peptide on Bcl-x(L), which presents a 4.6-fold increase as compared to the parent peptide affinity, was obtained when Ile85 was mutated with a 4-chlorophenylalanine. Finally, assays of eight Bak peptide analogues on Bcl-2 allowed us to postulate that modulations at position 78 could afford peptides with a binding selectivity enhanced for Bcl-x(L). These pharmacological and physicochemical parameter data should prove useful for the rational design of non-peptide ligands as potential antagonists of Bcl-2 protein interactions.
authors: INSERM, U554, Montpellier, F-34090, France.
authors: Virginie
authors: V
authors: Frey
authors: Julien
authors: J
authors: Viaud
authors: Guy
authors: G
authors: Subra
authors: Nicolas
authors: N
authors: Cauquil
authors: Jean-François
authors: JF
authors: Guichou
authors: Patrick
authors: P
authors: Casara
authors: Gérard
authors: G
authors: Grassy
authors: Alain
authors: A
authors: Chavanieu
mesh_terms: D019943:Amino Acid Substitution; D002942:Circular Dichroism; D005454:Fluorescence Polarization; D009154:Mutation; D009842:Oligopeptides / Q000737:chemistry* / Q000235:genetics; D010456:Peptides, Cyclic / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000737:chemistry; D013329:Structure-Activity Relationship; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000737:chemistry*; D051020:bcl-X Protein / Q000737:chemistry
chemical_list: D009842:Oligopeptides; D010456:Peptides, Cyclic; D019253:Proto-Oncogene Proteins c-bcl-2; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051020:bcl-X Protein