An enzyme captured in two conformational states: crystal structure ofS-adenosyl-L-homocysteine hydrolase fromBradyrhizobium elkanii
- 26 November 2015
- journal article
- research article
- Published by International Union of Crystallography (IUCr) in Acta crystallographica. Section D, Structural biology
- Vol. 71 (12), 2422-2432
- https://doi.org/10.1107/s1399004715018659
Abstract
S-Adenosyl-L-homocysteine hydrolase (SAHase) is involved in the enzymatic regulation ofS-adenosyl-L-methionine (SAM)-dependent methylation reactions. After methyl-group transfer from SAM,S-adenosyl-L-homocysteine (SAH) is formed as a byproduct, which in turn is hydrolyzed to adenosine (Ado) and homocysteine (Hcy) by SAHase. The crystal structure of BeSAHase, an SAHase fromBradyrhizobium elkanii, which is a nitrogen-fixing bacterial symbiont of legume plants, was determined at 1.7 Å resolution, showing the domain organization (substrate-binding domain, NAD+cofactor-binding domain and dimerization domain) of the subunits. The protein crystallized in its biologically relevant tetrameric form, with three subunits in a closed conformation enforced by complex formation with the Ado product of the enzymatic reaction. The fourth subunit is ligand-free and has an open conformation. The BeSAHase structure therefore provides a unique snapshot of the domain movement of the enzyme induced by the binding of its natural ligands.Keywords
This publication has 41 references indexed in Scilit:
- REFMAC5 for the refinement of macromolecular crystal structuresActa crystallographica. Section D, Structural biology, 2011
- PHENIX: a comprehensive Python-based system for macromolecular structure solutionActa crystallographica. Section D, Structural biology, 2010
- XDSActa crystallographica. Section D, Structural biology, 2010
- electronic Ligand Builder and Optimization Workbench(eLBOW): a tool for ligand coordinate and restraint generationActa crystallographica. Section D, Structural biology, 2009
- PDBsum new thingsNucleic Acids Research, 2009
- Automated macromolecular model building for X-ray crystallography using ARP/wARP version 7Nature Protocols, 2008
- Inference of Macromolecular Assemblies from Crystalline StateJournal of Molecular Biology, 2007
- Phasercrystallographic softwareJournal of Applied Crystallography, 2007
- Coot: model-building tools for molecular graphicsActa crystallographica. Section D, Structural biology, 2004
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976