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1z9a

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Revision as of 10:41, 12 October 2017

Crystal Structure Of The Asn-309 To Asp Mutant Of Candida Tenuis Xylose Reductase (Akr2B5) Bound To Nad+

Structural highlights

1z9a is a 4 chain structure with sequence from Atcc 10573. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Gene:	XYL1, XYLR (ATCC 10573)
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[XYL1_CANTE] Reduces D-xylose into xylitol. Has a preference for NADPH, but can also utilize NADH as cosubstrate.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Little is known about how substrates bind to CtXR (Candida tenuis xylose reductase; AKR2B5) and other members of the AKR (aldo-keto reductase) protein superfamily. Modelling of xylose into the active site of CtXR suggested that Trp23, Asp50 and Asn309 are the main components of pentose-specific substrate-binding recognition. Kinetic consequences of site-directed substitutions of these residues are reported. The mutants W23F and W23Y catalysed NADH-dependent reduction of xylose with only 4 and 1% of the wild-type efficiency (kcat/K(m)) respectively, but improved the wild-type selectivity for utilization of ketones, relative to xylose, by factors of 156 and 471 respectively. Comparison of multiple sequence alignment with reported specificities of AKR members emphasizes a conserved role of Trp23 in determining aldehyde-versus-ketone substrate selectivity. D50A showed 31 and 18% of the wild-type catalytic-centre activities for xylose reduction and xylitol oxidation respectively, consistent with a decrease in the rates of the chemical steps caused by the mutation, but no change in the apparent substrate binding constants and the pattern of substrate specificities. The 30-fold preference of the wild-type for D-galactose compared with 2-deoxy-D-galactose was lost completely in N309A and N309D mutants. Comparison of the 2.4 A (1 A=0.1 nm) X-ray crystal structure of mutant N309D bound to NAD+ with the previous structure of the wild-type holoenzyme reveals no major structural perturbations. The results suggest that replacement of Asn309 with alanine or aspartic acid disrupts the function of the original side chain in donating a hydrogen atom for bonding with the substrate C-2(R) hydroxy group, thus causing a loss of transition-state stabilization energy of 8-9 kJ/mol.

Probing the substrate binding site of Candida tenuis xylose reductase (AKR2B5) with site-directed mutagenesis.,Kratzer R, Leitgeb S, Wilson DK, Nidetzky B Biochem J. 2006 Jan 1;393(Pt 1):51-8. PMID:16336198^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Kratzer R, Leitgeb S, Wilson DK, Nidetzky B. Probing the substrate binding site of Candida tenuis xylose reductase (AKR2B5) with site-directed mutagenesis. Biochem J. 2006 Jan 1;393(Pt 1):51-8. PMID:16336198 doi:10.1042/BJ20050831

1 Structural highlights
2 Function
3 Evolutionary Conservation
4 Publication Abstract from PubMed
5 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1z9a"

@@ Line 1: / Line 1: @@
 ==Crystal Structure Of The Asn-309 To Asp Mutant Of Candida Tenuis Xylose Reductase (Akr2B5) Bound To Nad+==
 <StructureSection load='1z9a' size='340' side='right' caption='[[1z9a]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
@@ Line 5: / Line 6: @@
 </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=NAD:NICOTINAMIDE-ADENINE-DINUCLEOTIDE'>NAD</scene></td></tr>
 <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">XYL1, XYLR ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=45596 ATCC 10573])</td></tr>
-<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1z9a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1z9a OCA], [http://pdbe.org/1z9a PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1z9a RCSB], [http://www.ebi.ac.uk/pdbsum/1z9a PDBsum]</span></td></tr>
+<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1z9a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1z9a OCA], [http://pdbe.org/1z9a PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1z9a RCSB], [http://www.ebi.ac.uk/pdbsum/1z9a PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1z9a ProSAT]</span></td></tr>
 </table>
 == Function ==

1z9a

From Proteopedia

Revision as of 10:41, 12 October 2017

Crystal Structure Of The Asn-309 To Asp Mutant Of Candida Tenuis Xylose Reductase (Akr2B5) Bound To Nad+

Structural highlights

Function

Evolutionary Conservation

Publication Abstract from PubMed

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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