2IHT

Carboxyethylarginine synthase from Streptomyces clavuligerus: SeMet structure

Summary for 2IHT

• Entry DOI: 10.2210/pdb2iht/pdb
• Descriptor: Carboxyethylarginine synthase, MAGNESIUM ION, SULFATE ION, ... (6 entities in total)
• Functional Keywords: thiamin diphosphate complex, transferase
• Biological source: Streptomyces clavuligerus
• Total number of polymer chains: 4
• Total formula weight: 248858.04

Authors

Caines, M.E.,Schofield, C.J. (deposition date: 2006-09-27, release date: 2007-09-18, Last modification date: 2024-10-30)

Primary citation

Caines, M.E.,Sorensen, J.L.,Schofield, C.J.
Structural and mechanistic studies on N(2)-(2-carboxyethyl)arginine synthase.
Biochem.Biophys.Res.Commun., 385:512-517, 2009

PubMed Abstract: N(2)-(2-Carboxyethyl)arginine synthase (CEAS), an unusual thiamin diphosphate (ThDP)-dependent enzyme, catalyses the committed step in the biosynthesis of the b-lactamase inhibitor clavulanic acid in Streptomyces clavuligerus. Crystal structures of tetrameric CEAS-ThDP in complex with the substrate analogues 5-guanidinovaleric acid (GVA) and tartrate, and a structure reflecting a possible enol(ate)-ThDP reaction intermediate are described. The structures suggest overlapping binding sites for the substrates D-glyceraldehyde-3-phosphate (D-G3P) and L-arginine, and are consistent with the proposed CEAS mechanism in which D-G3P binds at the active site and reacts to form an alpha,beta-unsaturated intermediate,which subsequently undergoes (1,4)-Michael addition with the alpha-amino group of L-arginine. Additional solution studies are presented which probe the amino acid substrate tolerance of CEAS, providing further insight into the L-arginine binding site. These findings may facilitate the engineering of CEAS towards the synthesis of alternative beta-amino acid products.

PubMed: 19477162
DOI: 10.1016/j.bbrc.2009.05.095

Experimental method

X-RAY DIFFRACTION (2 Å)