Format

Send to

Choose Destination
J Biotechnol. 2016 Oct 10;235:24-31. doi: 10.1016/j.jbiotec.2016.04.013. Epub 2016 Apr 8.

Structures of almond hydroxynitrile lyase isoenzyme 5 provide a rationale for the lack of oxidoreductase activity in flavin dependent HNLs.

Author information

1
ACIB GmbH, Petersgasse 14, 8010 Graz, Austria; Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50/3, 8010 Graz, Austria.
2
DSM, Alexander Flemingplaan 1, 2613 AX Delft, Netherlands.
3
ACIB GmbH, Petersgasse 14, 8010 Graz, Austria; Research Unit Functional Proteomics and Metabolic Pathways, Institute of Pathology, Medical University of Graz, Omics Center Graz, BioTechMed-Graz, Stiftingtalstrasse 24, 8010 Graz, Austria.
4
ACIB GmbH, Petersgasse 14, 8010 Graz, Austria; Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50/3, 8010 Graz, Austria. Electronic address: karl.gruber@uni-graz.at.

Abstract

Hydroxynitrile lyases (HNLs) catalyze the asymmetric addition of HCN to aldehydes producing enantiomerically pure cyanohydrins. These enzymes can be heterologously expressed in large quantities making them interesting candidates for industrial applications. The HNLs from Rosaceae evolved from flavin dependent dehydrogenase/oxidase structures. Here we report the high resolution X-ray structure of the highly glycosylated Prunus amygdalus HNL isoenzyme5 (PaHNL5 V317A) expressed in Aspergillus niger and its complex with benzyl alcohol. A comparison with the structure of isoenzyme PaHNL1 indicates a higher accessibility to the active site and a larger cavity for PaHNL5. Additionally, the PaHNL5 complex structure with benzyl alcohol was compared with the structurally related aryl-alcohol oxidase (AAO). Even though both enzymes contain an FAD-cofactor and histidine residues at crucial positions in the active site, PaHNL5 lacks the oxidoreductase activity. The structures indicate that in PaHNLs benzyl alcohol is bound too far away from the FAD cofactor in order to be oxidized.

KEYWORDS:

Benzyl alcohol; Hydroxynitrile lyase; Prunus amygdalus; X-ray structure

PMID:
27067080
DOI:
10.1016/j.jbiotec.2016.04.013
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center