%0 Journal Article
%T A Surface Groove Essential for Viral Bcl-2 Function During Chronic Infection In Vivo
%A Joy Loh equal contributor
%A Qiulong Huang equal contributor
%A Andrew M Petros
%A David Nettesheim
%A Linda F. van Dyk
%A Lucia Labrada
%A Samuel H Speck
%A Beth Levine
%A Edward T Olejniczak £¿
%A Herbert W Virgin IV £¿
%J PLOS Pathogens
%D 2005
%I Public Library of Science (PLoS)
%R 10.1371/journal.ppat.0010010
%X Antiapoptotic Bcl-2 family proteins inhibit apoptosis in cultured cells by binding BH3 domains of proapoptotic Bcl-2 family members via a hydrophobic BH3 binding groove on the protein surface. We investigated the physiological importance of the BH3 binding groove of an antiapoptotic Bcl-2 protein in mammals in vivo by analyzing a viral Bcl-2 family protein. We show that the ¦Ã-herpesvirus 68 (¦ÃHV68) Bcl-2 family protein (¦ÃHV68 v-Bcl-2), which is known to inhibit apoptosis in cultured cells, inhibits both apoptosis in primary lymphocytes and Bax toxicity in yeast. Nuclear magnetic resonance determination of the ¦ÃHV68 v-Bcl-2 structure revealed a BH3 binding groove that binds BH3 domain peptides from proapoptotic Bcl-2 family members Bax and Bak via a molecular mechanism shared with host Bcl-2 family proteins, involving a conserved arginine in the BH3 peptide binding groove. Mutations of this conserved arginine and two adjacent amino acids to alanine (SGR to AAA) within the BH3 binding groove resulted in a properly folded protein that lacked the capacity of the wild-type ¦ÃHV68 v-Bcl-2 to bind Bax BH3 peptide and to block Bax toxicity in yeast. We tested the physiological importance of this v-Bcl-2 domain during viral infection by engineering viral mutants encoding a v-Bcl-2 containing the SGR to AAA mutation. This mutation resulted in a virus defective for both efficient reactivation of ¦ÃHV68 from latency and efficient persistent ¦ÃHV68 replication. These studies demonstrate an essential functional role for amino acids in the BH3 peptide binding groove of a viral Bcl-2 family member during chronic infection.
%U http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.0010010