[NMR paper] NMR studies of Interactions between Bax and BH3 domain-containing peptides in the absence and presence of CHAPS.

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NMR studies of Interactions between Bax and BH3 domain-containing peptides in the absence and presence of CHAPS.

NMR studies of Interactions between Bax and BH3 domain-containing peptides in the absence and presence of CHAPS.

Arch Biochem Biophys. 2014 Jan 13;

Authors: Yao S, Westphal D, Babon JJ, Thompson GV, Robin AY, Adams JM, Colman PM, Czabotar PE

Abstract
Activation and oligomerisation of Bax, a key pro-apoptotic Bcl-2 family protein, are key steps in the mitochondrial pathway to apoptosis. The signals for apoptosis are conveyed by the distantly related BH3-only proteins, which use their short BH3 domain, an amphipathic alpha-helix, to interact with other Bcl-2 family members. Here we report an NMR study of interactions between Bax-deltaC and BH3 domain-containing peptides in the absence and presence of CHAPS, a zwitterionic detergent. We find for the first time that CHAPS interacts weakly with Bax-deltaC (fast exchange on the NMR chemical shift timescale), at concentrations below micelle formation and with an estimated Kd in the tens of mM. Direct and relatively strong- interactions (slow exchange on the NMR chemical shift timescale) were also observed for Bax-deltaC with BaxBH3 (estimated Kd of circa 150 ?M) or BimBH3 in the absence of CHAPS. The interaction with either peptide alone induced widespread chemical shift perturbations to Bax-deltaC in solution which implies that Bax-deltaC might have undergone significant conformation change upon binding the BH3 peptide. However, Bax-deltaC remained monomeric upon binding either CHAPS or a BH3 peptide alone, but the presence of both provoked it to form a dimer.


PMID: 24434006 [PubMed - as supplied by publisher]



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