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Publication Abstract from PubMed

Haloacid dehalogenases are potentially involved in bioremediation of contaminated environments and few have been biochemically characterized from marine organisms. The L-2-haloacid dehalogenase (L-2-HAD) from the marine Bacteroidetes Zobellia galactanivorans Dsij(T) (ZgHAD) has been shown to catalyze the dehalogenation of C2 and C3 short-chain L-2-haloalkanoic acids. To better understand its catalytic properties, its enzymatic stability, active site and 3D structure were analyzed. ZgHAD demonstrates high stability to solvents and a conserved catalytic activity when heated up to 60 degrees C, its melting temperature being at 65 degrees C. The X-ray structure of the recombinant enzyme was solved by molecular replacement. The enzyme folds as a homodimer and its active site is very similar to DehRhb, the other known L-2-HAD from a marine Rhodobacteraceae. Marked differences are present in the putative substrate entrance sites of the two enzymes. The H179 amino acid potentially involved in the activation of a catalytic water molecule was confirmed as catalytic amino acid through the production of two inactive site-directed mutants. The crystal packing of 13 dimers in the asymmetric unit of an active-site mutant, ZgHAD-H179N, reveals domain movements of the monomeric subunits relative to each other. The involvement of a catalytic His/Glu dyad and substrate binding amino acids was further confirmed by computational docking. All together our results give new insights into the catalytic mechanism of the group of marine L-2-HAD. This article is protected by copyright. All rights reserved.

X-ray structure and mechanism of ZgHAD, a L-2-haloacid dehalogenase from the marine Flavobacterium Zobellia galactanivorans.,Grigorian E, Roret T, Czjzek M, Leblanc C, Delage L Protein Sci. 2022 Dec 10:e4540. doi: 10.1002/pro.4540. PMID:36502283^[1]

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