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Inter-domain communication of human cystathionine β-synthase: structural basis of S-adenosyl-L-methionine activation

DOI: 10.1074/jbc.M114.610782 DOI Help
PMID: 25336647 PMID Help

Authors: Thomas Mccorvie (University of Oxford) , Jolanta Kopec (University of Oxford) , S J Hyung (Worldwide Research and Development, Pfizer Inc.,) , Fiona Fitzpatrick (University of Oxford) , X Feng (Worldwide Research and Development, Pfizer Inc.,) , D. Termine (Pfizer Rare Disease Research Unit) , C. Strain-Damerell (University of Oxford) , Melanie Vollmar (Structural Genomics Consortium, University of Oxford, Diamond Light Source) , J. Fleming (Pfizer Rare Disease Research Unit) , J. M. Janz (Pfizer Rare Disease Research Unit) , C. Bulawa (Pfizer Rare Disease Research Unit) , Wyatt Yue (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Biological Chemistry , VOL 289 (52) , PAGES 36018 - 36030

State: Published (Approved)
Published: December 2014
Diamond Proposal Number(s): 8421 , 10619

Open Access Open Access

Abstract: Cystathionine β-synthase (CBS) is a key enzyme in sulfur metabolism, and its inherited deficiency causes homocystinuria. Mammalian CBS is modulated by the binding of S-adenosyl-l-methionine (AdoMet) to its regulatory domain, which activates its catalytic domain. To investigate the underlying mechanism, we performed x-ray crystallography, mutagenesis, and mass spectrometry (MS) on human CBS. The 1.7 Å structure of a AdoMet-bound CBS regulatory domain shows one AdoMet molecule per monomer, at the interface between two constituent modules (CBS-1, CBS-2). AdoMet binding is accompanied by a reorientation between the two modules, relative to the AdoMet-free basal state, to form interactions with AdoMet via residues verified by mutagenesis to be important for AdoMet binding (Phe443, Asp444, Gln445, and Asp538) and for AdoMet-driven inter-domain communication (Phe443, Asp538). The observed structural change is further supported by ion mobility MS, showing that as-purified CBS exists in two conformational populations, which converged to one in the presence of AdoMet. We therefore propose that AdoMet-induced conformational change alters the interface and arrangement between the catalytic and regulatory domains within the CBS oligomer, thereby increasing the accessibility of the enzyme active site for catalysis.

Journal Keywords: Allosteric Regulation; Conformational Change; Crystallography; Enzyme; Mass Spectrometry (MS); S-adenosyl-l-methionine (AdoMet); Activation; Cystathionine β-Synthase; SAM

Diamond Keywords: Enzymes

Subject Areas: Biology and Bio-materials, Chemistry

Instruments: I02-Macromolecular Crystallography , I04-Macromolecular Crystallography

Added On: 30/03/2015 09:26


Discipline Tags:

Biochemistry Chemistry Structural biology Life Sciences & Biotech

Technical Tags:

Diffraction Macromolecular Crystallography (MX)