Novel Bcl-2 Homology-3 Domain-like Sequences Identified from Screening Randomized Peptide Libraries for Inhibitors of the Pro-survival Bcl-2 Proteins
Details
Publication Year 2009-11-06, Volume 284, Issue #45, Page 31315-31326
Journal Title
JOURNAL OF BIOLOGICAL CHEMISTRY
Publication Type
Journal Article
Abstract
Interactions between Bcl-2 homology-3 (BH3)-only proteins and their pro-survival Bcl-2 family binding partners initiate the intrinsic apoptosis pathway. These interactions are mediated by a short helical motif, the BH3 domain, on the BH3-only protein, which inserts into a hydrophobic groove on the pro-survival molecule. To identify novel peptidic ligands that bind Mcl-1, a pro-survival protein relative of Bcl-2, both human and mouse Mcl-1 were screened against large randomized phage-displayed peptide libraries. We identified a number of 16-mer peptides with sub-micromolar affinity that were highly selective for Mcl-1, as well as being somewhat selective for the species of Mcl-1 (human or mouse) against which the library was panned. Interestingly, these sequences all strongly resembled natural BH3 domain sequences. By switching residues within the best of the human Mcl-1-binding sequences, or extending beyond the core sequence identified, we were able to alter the pro-survival protein interaction profile of this peptide such that it now bound all members tightly and was a potent killer when introduced into cells. Introduction of an amide lock constraint within this sequence also increased its helicity and binding to pro-survival proteins. These data provide new insights into the determinants of BH3 domain: pro-survival protein affinity and selectivity.
Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Keywords
BH3-ONLY PROTEINS; BH3 DOMAINS; SCANNING MUTAGENESIS; FAMILY PROTEINS; BAX ACTIVATION; PHAGE DISPLAY; APOPTOSIS; BINDING; MCL-1; ANTAGONISTS
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Creation Date: 2009-11-06 12:00:00
Last Modified: 0001-01-01 12:00:00
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