1nxq
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(New page: 200px<br /><applet load="1nxq" size="450" color="white" frame="true" align="right" spinBox="true" caption="1nxq, resolution 1.79Å" /> '''Crystal Structure of...)
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Revision as of 21:52, 24 November 2007
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Crystal Structure of R-alcohol dehydrogenase (RADH) (apoenyzme) from Lactobacillus brevis
Overview
The crystal structure of the apo-form of an R-specific alcohol, dehydrogenase from Lactobacillus brevis (LB-RADH) was solved and refined, to 1.8A resolution. LB-RADH is a member of the short-chain, dehydrogenase/reductase (SDR) enyzme superfamily. It is a homotetramer, with 251 amino acid residues per subunit and uses NADP(H) as co-enzyme., NADPH and the substrate acetophenone were modelled into the active site., The enantiospecificity of the enzyme can be explained on the basis of the, resulting hypothetical ternary complex. In contrast to most other SDR, enzymes, the catalytic activity of LB-RADH depends strongly on the binding, of Mg(2+). Mg(2+) removal by EDTA inactivates the enzyme completely. In, the crystal structure, the Mg(2+)-binding site is well defined. The ion, has a perfect octahedral coordination sphere and occupies a special, position concerning crystallographic and molecular point symmetry, meaning, that each RADH tetramer contains two magnesium ions. The magnesium ion is, no direct catalytic cofactor. However, it is structurally coupled to the, putative C-terminal hinge of the substrate-binding loop and, via an, extended hydrogen bonding network, to some side-chains forming the, substrate binding region. Therefore, the presented structure of apo-RADH, provides plausible explanations for the metal dependence of the enzyme.
About this Structure
1NXQ is a Single protein structure of sequence from Lactobacillus brevis with MG as ligand. Active as Alcohol dehydrogenase (NADP(+)), with EC number 1.1.1.2 Full crystallographic information is available from OCA.
Reference
The crystal structure of R-specific alcohol dehydrogenase from Lactobacillus brevis suggests the structural basis of its metal dependency., Niefind K, Muller J, Riebel B, Hummel W, Schomburg D, J Mol Biol. 2003 Mar 21;327(2):317-28. PMID:12628239
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