Intermonomer hydrogen bonds enhance GxxxG-driven dimerization of the BNIP3 transmembrane domain: roles for sequence context in helix-helix association in membranes.

ABSTRACT: We determined the sequence dependence of human BNIP3 transmembrane domain dimerization using the biological assay TOXCAT. Mutants in which intermonomer hydrogen bonds between Ser172 and His173 are abolished show moderate interaction, indicating that side-chain hydrogen bonds contribute to dimer stability but are not essential to dimerization. Mutants in which a GxxxG motif composed of Gly180 and Gly184 has been abolished show little or no interaction, demonstrating the critical nature of the GxxxG motif to BNIP3 dimerization. These findings show that side-chain hydrogen bonds can enhance the intrinsic dimerization of a GxxxG motif and that sequence context can control how hydrogen bonds influence helix-helix interactions in membranes. The dimer interface mapped by TOXCAT mutagenesis agrees

SUBMITTER: Lawrie CM 

PROVIDER: S-EPMC2836233 | biostudies-literature | 2010 Mar

REPOSITORIES: biostudies-literature