1id8
From Proteopedia
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NMR STRUCTURE OF GLUTAMATE MUTASE (B12-BINDING SUBUNIT) COMPLEXED WITH THE VITAMIN B12 NUCLEOTIDE
Overview
Glutamate mutase from Clostridium tetanomorphum binds coenzyme B(12) in a, base-off/His-on form, in which the nitrogenous ligand of the, B(12)-nucleotide function is displaced from cobalt by a conserved, histidine. The effect of binding the B(12)-nucleotide moiety to MutS, the, B(12)-binding subunit of glutamate mutase, was investigated using NMR, spectroscopic methods. Binding of the B(12)-nucleotide to MutS was, determined to occur with K(d)=5.6(+/-0.7) mM and to be accompanied by a, specific conformational change in the protein. The nucleotide binding, cleft of the apo-protein, which is formed by a dynamic segment with, propensity for partial alpha-helical conformation (the "nascent", alpha-helix), becomes completely structured upon binding of the, B(12)-nucleotide, with formation of helix alpha1. In contrast, the segment, containing the conserved residues of the B(12)-binding Asp-x-His-x-x-Gly, motif remains highly dynamic in the protein/B(12)-nucleotide complex. From, relaxation studies, the time constant tau, which characterizes the time, scale for the formation of helix alpha1, was estimated to be about 30, micros (15)N and was the same in both, apo-protein and nucleotide-bound, protein. Thus, the binding of the B(12)-nucleotide moiety does not, significantly alter the kinetics of helix formation, but only shifts the, equilibrium towards the structured fold. These results indicate MutS to be, structured in such a way, as to be able to trap the nucleotide segment of, the base-off form of coenzyme B(12) and provide, accordingly, the first, structural clues as to how the process of B(12)-binding occurs.
About this Structure
1ID8 is a Single protein structure of sequence from Clostridium tetanomorphum with FOP and DBI as ligands. Active as Methylaspartate mutase, with EC number 5.4.99.1 Full crystallographic information is available from OCA.
Reference
The B(12)-binding subunit of glutamate mutase from Clostridium tetanomorphum traps the nucleotide moiety of coenzyme B(12)., Tollinger M, Eichmuller C, Konrat R, Huhta MS, Marsh EN, Krautler B, J Mol Biol. 2001 Jun 8;309(3):777-91. PMID:11397096
Page seeded by OCA on Tue Nov 20 17:18:21 2007
