Xylose reductase (XR; AKR2B5) is an unusual member of aldo-keto reductase superfamily, because it is one of the few able to efficiently utilize both NADPH and NADH as co-substrates in converting xylose into xylitol. In order to better understand the basis for this dual specificity, we have determined the crystal structure of XR from the yeast Candida tenuis in complex with NAD+ to 1.80 Å resolution (where 1 Å=0.1 nm) with a crystallographic R-factor of 18.3%. A comparison of the NAD+- and the previously determined NADP+-bound forms of XR reveals that XR has the ability to change the conformation of two loops. To accommodate both the presence and absence of the 2′-phosphate, the enzyme is able to adopt different conformations for several different side chains on these loops, including Asn276, which makes alternative hydrogen-bonding interactions with the adenosine ribose. Also critical is the presence of Glu227 on a short rigid helix, which makes hydrogen bonds to both the 2′- and 3′-hydroxy groups of the adenosine ribose. In addition to changes in hydrogen-bonding of the adenosine, the ribose unmistakably adopts a 3′-endo conformation rather than the 2′-endo conformation seen in the NADP+-bound form. These results underscore the importance of tight adenosine binding for efficient use of either NADH or NADPH as a co-substrate in aldo-keto reductases. The dual specificity found in XR is also an important consideration in designing a high-flux xylose metabolic pathway, which may be improved with an enzyme specific for NADH.
Skip Nav Destination
Follow us on Twitter @Biochem_Journal
Article navigation
July 2003
- PDF Icon PDF LinkFront Matter
Research Article|
July 15 2003
Structure of xylose reductase bound to NAD+ and the basis for single and dual co-substrate specificity in family 2 aldo-keto reductases
Kathryn L. KAVANAGH;
Kathryn L. KAVANAGH
∗Section of Molecular and Cellular Biology, University of California, Davis, CA 95616, U.S.A.
Search for other works by this author on:
Mario KLIMACEK;
Mario KLIMACEK
†Institute of Biotechnology, Graz University of Technology, Petersgasse 12, A-8010 Graz, Austria
Search for other works by this author on:
Bernd NIDETZKY;
Bernd NIDETZKY
†Institute of Biotechnology, Graz University of Technology, Petersgasse 12, A-8010 Graz, Austria
Search for other works by this author on:
David K. WILSON
David K. WILSON
1
∗Section of Molecular and Cellular Biology, University of California, Davis, CA 95616, U.S.A.
1To whom correspondence should be addressed (e-mail [email protected]).
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
February 19 2003
Revision Received:
May 01 2003
Accepted:
May 06 2003
Accepted Manuscript online:
May 06 2003
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London ©2003
2003
Biochem J (2003) 373 (2): 319–326.
Article history
Received:
February 19 2003
Revision Received:
May 01 2003
Accepted:
May 06 2003
Accepted Manuscript online:
May 06 2003
Citation
Kathryn L. KAVANAGH, Mario KLIMACEK, Bernd NIDETZKY, David K. WILSON; Structure of xylose reductase bound to NAD+ and the basis for single and dual co-substrate specificity in family 2 aldo-keto reductases. Biochem J 15 July 2003; 373 (2): 319–326. doi: https://doi.org/10.1042/bj20030286
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Biochemical Society Member Sign in
Sign InSign in via your Institution
Sign in via your InstitutionGet Access To This Article
Follow us on Twitter @Biochem_Journal
Open Access for all
We offer compliant routes for all authors from 2025. With library support, there will be no author nor reader charges in 5 journals. Check here |
![]() View past webinars > |