Identification of catalytically important residues of the carotenoid 1,2-hydratases from Rubrivivax gelatinosus and Thiocapsa roseopersicina

Identification of catalytically important residues of the carotenoid 1,2-hydratases from Rubrivivax gelatinosus and Thiocapsa roseopersicina

Hiseni, A.
Otten, L.G.
Arends, I.W.C.E.

Applied Sciences

BT/Biotechnology

2015-10-19

Carotenoid 1,2-hydratases (CrtC) catalyze the selective addition of water to an isolated carbon–carbon double bond. Although their involvement in the carotenoid biosynthetic pathway is well understood, little is known about the mechanism by which these hydratases transform carotenoids such as lycopene into the corresponding hydroxyl compounds. Key residues were identified at positions His239, Trp241, Tyr266, and Asp268 in CrtC from Rubrivivax gelatinosus (and corresponding positions in Thiocapsa roseopersicina). Alanine mutants at these positions were found to be completely inactive, suggesting their direct involvement in the catalytic reaction. Our resulting mechanistic hypothesis is in analogy with the recently studied class of terpenoid cyclase enzymes containing a highly acidic aspartic residue in their active site. We propose that a similar aspartic acid residue, which is conserved through all putative CrtCs, is involved in initial protonation of the double bond in lycopene.

carotenoid 1,2-hydratase
CrtC
hydro-lyase
enzyme mechanism
biocatalysis

http://resolver.tudelft.nl/uuid:ca463350-080f-453f-9790-75c5195ac8e7

Springer

0175-7598

https://doi.org/10.1007/s00253-015-6998-y

Applied Microbiology and Biotechnology, 100 (3), 2016

Institutional Repository

journal article

(c) 2015 The Author(s)
This article is published with open access at Springerlink.com