Download MendeleyAn enzyme captured in two conformational states: crystal structure of S-adenosyl-L-homocysteine hydrolase from Bradyrhizobium elkanii.
Manszewski, T., Singh, K., Imiolczyk, B., Jaskolski, M.(2015) Acta Crystallogr D Biol Crystallogr 71: 2422-2432
- PubMed: 26627650
- DOI: https://doi.org/10.1107/S1399004715018659
- Primary Citation of Related Structures:
4LVC - PubMed Abstract:
S-Adenosyl-L-homocysteine hydrolase (SAHase) is involved in the enzymatic regulation of S-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 from Bradyrhizobium 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.
Organizational Affiliation:
Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland.
