title: Xylella fastidiosa esterase rather than hydroxynitrile lyase.
abstract: In 2009, we reported that the product of the gene SCJ21.16 (XFa0032) from Xylella fastidiosa, a xylem-restricted plant pathogen that causes a range of diseases in several important crops, encodes a protein (XfHNL) with putative hydroxynitrile lyase activity. Sequence analysis and activity tests indicated that XfHNL exhibits an α/β-hydrolase fold and could be classified as a member of the family of FAD-independent HNLs. Here we provide a more detailed sequence analysis and new experimental data. Using pure heterologously expressed XfHNL we show that this enzyme cannot catalyse the cleavage/synthesis of mandelonitrile and that this protein is in fact a non-enantioselective esterase. Homology modelling and ligand docking simulations were used to study the active site and support these results. This finding could help elucidate the common ancestor of esterases and hydroxynitrile lyases with an α/β -hydrolase fold.
authors: Gebouw voor Scheikunde, Biokatalyse Afdeling Biotechnologie, Technische Universiteit Delft, Julianalaan 136, 2628 BL Delft (The Netherlands). G.TorreloVilla@tudelft.nl.
authors: Guzman
authors: G
authors: Torrelo
authors: Fayene Zeferino
authors: FZ
authors: Ribeiro de Souza
authors: Emanuel
authors: E
authors: Carrilho
authors: Ulf
authors: U
authors: Hanefeld
mesh_terms: D000446:Aldehyde-Lyases / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D004950:Esterases / Q000737:chemistry / Q000378:metabolism*; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D011487:Protein Conformation; D016415:Sequence Alignment; D044167:Xylella / Q000737:chemistry / Q000201:enzymology*
chemical_list: D004950:Esterases; D000446:Aldehyde-Lyases; C021541:mandelonitrile lyase
keywords: Xylella fastidiosa; docking simulation; enzyme models; esterases; lyases; protein structures