1pyf
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(New page: 200px<br /><applet load="1pyf" size="450" color="white" frame="true" align="right" spinBox="true" caption="1pyf, resolution 1.8Å" /> '''Structure of NADPH-de...)
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Revision as of 22:06, 20 November 2007
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Structure of NADPH-dependent family 11 aldo-keto reductase AKR11A(apo)
Overview
Aldo-keto reductases (AKRs) are a large superfamily of NAD(P)H-dependent, enzymes that function in a wide range of biological processes. The, structures of two enzymes from the previously uncharacterized family 11, (AKR11A and AKR11B), the products of the iolS and yhdN genes of Bacillus, subtilis have been determined. AKR11B appears to be a relatively, conventional member of the superfamily with respect to structural and, biochemical properties. It is an efficient enzyme, specific for NADPH and, possesses a catalytic triad typical for AKRs. AKR11A exhibits catalytic, divergence from the other members of the superfamily and, surprisingly, AKR11B, the most closely related aldo-keto reductase in sequence. Although, both have conserved catalytic residues consisting of an acidic tyrosine, a, lysine and an aspartate, a water molecule interrupts this triad in, cofactor-bound AKR11A by inserting between the lysine and tyrosine, side-chains. This results in a unique architecture for an AKR active site, with scant catalytic power. In addition, the absence of a bulky tryptophan, side-chain in AKR11A allows an unconventional conformation of the bound, NADP+ cosubstrate, raising the possibility that it donates the 4-pro-S, hydride rather than the 4-pro-R hydride seen in most other AKRs. Based, upon the architecture of the active site and the resulting reaction, velocities, it therefore appears that functioning as an efficient, oxido-reductase is probably not the primary role of AKR11A. A comparison, of the apo and holo forms of AKR11A demonstrates that the cosubstrate does, not play the dramatic role in active site assembly seen in other, superfamily members.
About this Structure
1PYF is a Single protein structure of sequence from Bacillus subtilis with NA and EDO as ligands. Full crystallographic information is available from OCA.
Reference
Structural and catalytic diversity in the two family 11 aldo-keto reductases., Ehrensberger AH, Wilson DK, J Mol Biol. 2004 Mar 26;337(3):661-73. PMID:15019785
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