1m2w
From Proteopedia
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Pseudomonas fluorescens mannitol 2-dehydrogenase ternary complex with NAD and D-mannitol
Overview
Long-chain mannitol dehydrogenases are secondary alcohol dehydrogenases, that are of wide interest because of their involvement in metabolism and, potential applications in agriculture, medicine, and industry. They differ, from other alcohol and polyol dehydrogenases because they do not contain a, conserved tyrosine and are not dependent on Zn(2+) or other metal, cofactors. The structures of the long-chain mannitol 2-dehydrogenase (54, kDa) from Pseudomonas fluorescens in a binary complex with NAD(+) and, ternary complex with NAD(+) and d-mannitol have been determined to, resolutions of 1.7 and 1.8 A and R-factors of 0.171 and 0.176, respectively. These results show an N-terminal domain that includes a, typical Rossmann fold. The C-terminal domain is primarily alpha-helical, and mediates mannitol binding. The electron lone pair of Lys-295 is, steered by hydrogen-bonding interactions with the amide oxygen of Asn-300, and the main-chain carbonyl oxygen of Val-229 to act as the general base., Asn-191 and Asn-300 are involved in a web of hydrogen bonding, which, precisely orients the mannitol O2 proton for abstraction. These residues, also aid in stabilizing a negative charge in the intermediate state and in, preventing the formation of nonproductive complexes with the substrate., The catalytic lysine may be returned to its unprotonated state using a, rectifying proton tunnel driven by Glu-292 oscillating among different, environments. Despite low sequence homology, the closest structural, neighbors are glycerol-3-phosphate dehydrogenase, N-(1-d-carboxylethyl)-l-norvaline dehydrogenase, UDP-glucose, dehydrogenase, and 6-phosphogluconate dehydrogenase, indicating a possible, evolutionary relationship among these enzymes.
About this Structure
1M2W is a Single protein structure of sequence from Pseudomonas fluorescens with NAD and MTL as ligands. Active as Mannitol 2-dehydrogenase, with EC number 1.1.1.67 Full crystallographic information is available from OCA.
Reference
Crystal structure of Pseudomonas fluorescens mannitol 2-dehydrogenase binary and ternary complexes. Specificity and catalytic mechanism., Kavanagh KL, Klimacek M, Nidetzky B, Wilson DK, J Biol Chem. 2002 Nov 8;277(45):43433-42. Epub 2002 Aug 23. PMID:12196534
Page seeded by OCA on Sun Nov 25 03:42:18 2007
