1gq7
PROCLAVAMINATE AMIDINO HYDROLASE FROM STREPTOMYCES CLAVULIGERUS
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OverviewOverview
During biosynthesis of the clinically used beta-lactamase inhibitor, clavulanic acid, one of the three steps catalysed by clavaminic acid, synthase is separated from the other two by a step catalysed by, proclavaminic acid amidino hydrolase (PAH), in which the guanidino group, of an intermediate is hydrolysed to give proclavaminic acid and urea. PAH, shows considerable sequence homology with the primary metabolic arginases, which hydrolyse arginine to ornithine and urea, but does not accept, arginine as a substrate. Like other members of the bacterial sub-family of, arginases, PAH is hexameric in solution and requires Mn2+ ions for, activity. Other metal ions, including Co2+, can substitute for Mn2+. Two, new substrates for PAH were identified, N-acetyl-(L)-arginine and, (3R)-hydroxy-N-acetyl-(L)-arginine. Crystal structures of PAH from, Streptomyces clavuligerus (at 1.75 A and 2.45 A resolution, where 1 A=0.1, nm) imply how it binds beta-lactams rather than the amino acid substrate, of the arginases from which it evolved. The structures also suggest how, PAH selects for a particular alcohol intermediate in the clavam, biosynthesis pathway. As observed for the arginases, each PAH monomer, consists of a core of beta-strands surrounded by alpha-helices, and its, active site contains a di-Mn2+ centre with a bridging water molecule, responsible for hydrolytic attack on to the guanidino group of the, substrate. Comparison of structures obtained under different conditions, reveals different conformations of a flexible loop, which must move to, allow substrate binding.
About this StructureAbout this Structure
1GQ7 is a Single protein structure of sequence from Streptomyces clavuligerus with MN as ligand. Active as Agmatinase, with EC number 3.5.3.11 Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
Oligomeric structure of proclavaminic acid amidino hydrolase: evolution of a hydrolytic enzyme in clavulanic acid biosynthesis., Elkins JM, Clifton IJ, Hernandez H, Doan LX, Robinson CV, Schofield CJ, Hewitson KS, Biochem J. 2002 Sep 1;366(Pt 2):423-34. PMID:12020346
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