PMID: 21639858

Authors:

Ambrosi E, Capaldi S, Bovi M, Saccomani G, Perduca M, Monaco HL

Title:

Structural changes in the BH3 domain of SOUL protein upon interaction with the anti-apoptotic protein Bcl-xL.

Journal:

Biochem J. 2011 Jun 6.

Abstract:

The SOUL protein is known to induce apoptosis by provoking the mitochondrial permeability transition and a sequence homologous to the Bcl-2 homology 3 (BH3) domains has been recently identified in it thus making it a potential new member of the BH3-only protein family. Here we present NMR, SPR and crystallographic evidence that a peptide spanning SOUL residues 147 - 172 interacts with the anti-apoptotic protein Bcl-xL. We have crystallized SOUL alone and the complex of its BH3 domain peptide with Bcl-xL and solved their three-dimensional structures. The SOUL monomer is a single domain organized as a distorted beta barrel with eight anti-parallel strands and two alpha helices. The BH3 domain extends across 15 residues at the end of the second helix and 8 amino acids in the chain following it. There are important structural differences in the BH3 domain in the intact SOUL molecule and the same sequence bound to Bcl-xL.