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Title: Epistatic mutations in PUMA BH3 drive an alternate binding mode to potently and selectively inhibit anti-apoptotic Bfl-1

Abstract

Overexpression of anti-apoptotic Bcl-2 family proteins contributes to cancer progression and confers resistance to chemotherapy. Small molecules that target Bcl-2 are used in the clinic to treat leukemia, but tight and selective inhibitors are not available for Bcl-2 paralog Bfl-1. Guided by computational analysis, we designed variants of the native BH3 motif PUMA that are > 150-fold selective for Bfl-1 binding. The designed peptides potently trigger disruption of the mitochondrial outer membrane in cells dependent on Bfl-1, but not in cells dependent on other anti-apoptotic homologs. High-resolution crystal structures show that designed peptide FS2 binds Bfl-1 in a shifted geometry, relative to PUMA and other binding partners, due to a set of epistatic mutations. FS2 modified with an electrophile reacts with a cysteine near the peptide-binding groove to augment specificity. Designed Bfl-1 binders provide reagents for cellular profiling and leads for developing enhanced and cell-permeable peptide or small-molecule inhibitors.

Authors:
ORCiD logo; ORCiD logo; ; ; ORCiD logo
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
NSFOTHERNIGMS
OSTI Identifier:
1368344
Resource Type:
Journal Article
Resource Relation:
Journal Name: eLife; Journal Volume: 6; Journal Issue: 2017
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Jenson, Justin M., Ryan, Jeremy A., Grant, Robert A., Letai, Anthony, and Keating, Amy E. Epistatic mutations in PUMA BH3 drive an alternate binding mode to potently and selectively inhibit anti-apoptotic Bfl-1. United States: N. p., 2017. Web. doi:10.7554/eLife.25541.
Jenson, Justin M., Ryan, Jeremy A., Grant, Robert A., Letai, Anthony, & Keating, Amy E. Epistatic mutations in PUMA BH3 drive an alternate binding mode to potently and selectively inhibit anti-apoptotic Bfl-1. United States. doi:10.7554/eLife.25541.
Jenson, Justin M., Ryan, Jeremy A., Grant, Robert A., Letai, Anthony, and Keating, Amy E. Thu . "Epistatic mutations in PUMA BH3 drive an alternate binding mode to potently and selectively inhibit anti-apoptotic Bfl-1". United States. doi:10.7554/eLife.25541.
@article{osti_1368344,
title = {Epistatic mutations in PUMA BH3 drive an alternate binding mode to potently and selectively inhibit anti-apoptotic Bfl-1},
author = {Jenson, Justin M. and Ryan, Jeremy A. and Grant, Robert A. and Letai, Anthony and Keating, Amy E.},
abstractNote = {Overexpression of anti-apoptotic Bcl-2 family proteins contributes to cancer progression and confers resistance to chemotherapy. Small molecules that target Bcl-2 are used in the clinic to treat leukemia, but tight and selective inhibitors are not available for Bcl-2 paralog Bfl-1. Guided by computational analysis, we designed variants of the native BH3 motif PUMA that are > 150-fold selective for Bfl-1 binding. The designed peptides potently trigger disruption of the mitochondrial outer membrane in cells dependent on Bfl-1, but not in cells dependent on other anti-apoptotic homologs. High-resolution crystal structures show that designed peptide FS2 binds Bfl-1 in a shifted geometry, relative to PUMA and other binding partners, due to a set of epistatic mutations. FS2 modified with an electrophile reacts with a cysteine near the peptide-binding groove to augment specificity. Designed Bfl-1 binders provide reagents for cellular profiling and leads for developing enhanced and cell-permeable peptide or small-molecule inhibitors.},
doi = {10.7554/eLife.25541},
journal = {eLife},
number = 2017,
volume = 6,
place = {United States},
year = {Thu Jun 08 00:00:00 EDT 2017},
month = {Thu Jun 08 00:00:00 EDT 2017}
}