1B1A

GLUTAMATE MUTASE (B12-BINDING SUBUNIT), NMR, MINIMIZED AVERAGE STRUCTURE

1B1A の概要

• エントリーDOI: 10.2210/pdb1b1a/pdb
• 分子名称: GLUTAMATE MUTASE (1 entity in total)
• 機能のキーワード: isomerase, glutamate mutase, b12-binding subunit
• 由来する生物種: Clostridium cochlearium
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 14830.05

構造登録者

Hoffmann, B.,Konrat, R.,Bothe, H.,Buckel, W.,Kraeutler, B. (登録日: 1998-11-19, 公開日: 1999-07-13, 最終更新日: 2024-04-10)

主引用文献

Hoffmann, B.,Konrat, R.,Bothe, H.,Buckel, W.,Krautler, B.
Structure and dynamics of the B12-binding subunit of glutamate mutase from Clostridium cochlearium.
Eur.J.Biochem., 263:178-188, 1999

PubMed Abstract: Glutamate mutase (Glm) is an adenosylcobamide-dependent enzyme that catalyzes the reversible rearrangement of (2S)-glutamate to (2S, 3S)-3-methylaspartate. The active enzyme from Clostridium cochlearium consists of two subunits (of 53.6 and 14.8 kDa) as an alpha2beta2 tetramer, whose assembly is mediated by coenzyme B12. The smaller of the protein components, GlmS, has been suggested to be the B12-binding subunit. Here we report the solution structure of GlmS, determined from a heteronuclear NMR-study, and the analysis of important dynamical aspects of this apoenzyme subunit. The global fold and dynamic behavior of GlmS in solution are similar to those of the corresponding subunit MutS from C. tetanomorphum, which has previously been investigated using NMR-spectroscopy. Both solution structures of the two Glm B12-binding subunits share striking similarities with that determined by crystallography for the B12-binding domain of methylmalonyl CoA mutase (Mcm) from Propionibacterium shermanii, which is B12 bound. In the crystal structure a conserved histidine residue was found to be coordinated to cobalt, displacing the endogenous axial ligand of the cobamide. However, in GlmS and MutS the sequence motif, Asp-x-His-x-x-Gly, which includes the cobalt-coordinating histidine residue, and a predicted alpha-helical region following the motif, are present as an unstructured and highly mobile loop. In the absence of coenzyme, the B12-binding site apparently is only partially formed. By comparing the crystal structure of Mcm with the solution structures of B12-free GlmS and MutS, a consistent picture on the mechanism of B12 binding has been obtained. Important elements of the binding site only become structured upon binding B12; these include the cobalt-coordinating histidine residue, and an alpha helix that forms one side of the cleft accommodating the nucleotide 'tail' of the coenzyme.

PubMed: 10429202
DOI: 10.1046/j.1432-1327.1999.00482.x

実験手法

SOLUTION NMR