Universität zu Köln

Richter, Nina ORCID: 0000-0001-5109-0710, Breicha, Klaus, Hummel, Werner and Niefind, Karsten ORCID: 0000-0002-0183-6315 (2010). The Three-Dimensional Structure of AKR11B4, a Glycerol Dehydrogenase from Gluconobacter oxydans, Reveals a Tryptophan Residue as an Accelerator of Reaction Turnover. J. Mol. Biol., 404 (3). S. 353 - 363. LONDON: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD. ISSN 1089-8638

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Abstract

The NADP-dependent glycerol dehydrogenase (EC 1.1.1.72) from Gluconobacter oxydans is a member of family 11 of the aldo-keto reductase (AKR) enzyme superfamily; according to the systematic nomenclature within the AICR superfamily, the term AKR11B4 has been assigned to the enzyme. AKR11B4 is a biotechnologically attractive enzyme because of its broad substrate spectrum, combined with its distinctive regioselectivity and stereoselectivity. These features can be partially rationalized based on a 2-angstrom crystal structure of apo-AKR11134, which we describe and interpret here against the functional complex structures of other members of family 11 of the AKR superfamily. The structure of AKR11B4 shows the AKR-typical (beta/alpha)(8) TIM-barrel fold, with three loops and the C-terminal tail determining the particular enzymatic properties. In comparison to AKR11B1 (its closest AKR relative), AKR11B4 has a relatively broad binding cleft for the cosubstrate NADP/NADPH. In the crystalline environment, it is completely blocked by the C-terminal segment of a neighboring protomer. The structure reveals a conspicuous tryptophan residue (Trp23) that has to adopt an unconventional and strained side-chain conformation to permit cosubstrate binding. We predict and confirm by site-directed mutagenesis that Trp23 is an accelerator of (co)substrate turnover. Furthermore, we show that, simultaneously, this tryptophan residue is a critical determinant for substrate binding by the enzyme, while enantioselectivity is probably governed by a methionine residue within the C-terminal tail. We present structural reasons for these notions based on ternary complex models of AKR11B4, NADP, and either octanal, D-glyceraldehyde, or L-glyceraldehyde. (c) 2010 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Richter, Nina UNSPECIFIED orcid.org/0000-0001-5109-0710 UNSPECIFIED Breicha, Klaus UNSPECIFIED UNSPECIFIED UNSPECIFIED Hummel, Werner UNSPECIFIED UNSPECIFIED UNSPECIFIED Niefind, Karsten UNSPECIFIED orcid.org/0000-0002-0183-6315 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-490840
DOI:	10.1016/j.jmb.2010.09.049
Journal or Publication Title:	J. Mol. Biol.
Volume:	404
Number:	3
Page Range:	S. 353 - 363
Date:	2010
Publisher:	ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
Place of Publication:	LONDON
ISSN:	1089-8638
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language HUMAN ALDOSE REDUCTASE; CRYSTAL-STRUCTURE; KETO; MUTAGENESIS; SITE Multiple languages Biochemistry & Molecular Biology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/49084