Three-dimensional structure of L-2-haloacid dehalogenase from Xanthobacter autotrophicus GJ10 complexed with the substrate-analogue formate.
The L-2-haloacid dehalogenase from the 1,2-dichloroethane degrading bacterium Xanthobacter autotrophicus GJ10 catalyzes the hydrolytic dehalogenation of small L-2-haloalkanoic acids to yield the corresponding D-2-hydroxyalkanoic acids. Its crystal structure was solved by the method of multiple isomorphous replacement with incorporation of anomalous scattering information and solvent flattening, and was refined at 1.95-A resolution to an R factor of 21.3%. The three-dimensional structure is similar to that of the homologous L-2-haloacid dehalogenase from Pseudomonas sp. YL (1), but the X. autotrophicus enzyme has an extra dimerization domain, an active site cavity that is completely shielded from the solvent, and a different orientation of several catalytically important amino acid residues. Moreover, under the conditions used, a formate ion is bound in the active site. The position of this substrate-analogue provides valuable information on the reaction mechanism and explains the limited substrate specificity of the Xanthobacter L-2-haloacid dehalogenase.
Ridder
I S
IS
Laboratory of Biophysical Chemistry, Department of Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Rozeboom
H J
HJ
Kalk
K H
KH
Janssen
D B
DB
Dijkstra
B W
BW
D001665:Binding Sites; D018360:Crystallography, X-Ray; D005561:Formates / Q000378:metabolism*; D016946:Gram-Negative Aerobic Rods and Cocci / Q000201:enzymology*; D006867:Hydrolases / Q000737:chemistry*; D008958:Models, Molecular; D011487:Protein Conformation; D011549:Pseudomonas / Q000201:enzymology; D013379:Substrate Specificity
D005561:Formates; C030544:formic acid; D006867:Hydrolases; C034507:2-haloacid dehalogenase