CRYSTALLOGRAPHIC ANALYSIS OF THE CATALYTIC MECHANISM OF HALOALKANE DEHALOGENASE

Article

关键词: XANTHOBACTER-AUTOTROPHICUS GJ10;    ALPHA-HELIX DIPOLE;    X-RAY-DIFFRACTION;    HALOGENATED ALKANES;    ENZYME INTERMEDIATE;    SERINE PROTEINASE;    CRYSTAL;    ACETYLCHOLINESTERASE;    PURIFICATION;    DEGRADATION;   

DOI  :  10.1038/363693a0

来源: SCIE

【 摘 要 】

Crystal structures of haloalkane dehalogenase were determined in the presence of the substrate 1,2-dichloroethane. At pH 5 and 4-degrees-C, substrate is bound in the active site without being converted; warming to room temperature causes the substrate's carbon-chlorine bond to be broken, producing a chloride ion with concomitant alkylation of the active-site residue Asp124. At pH 6 and room temperature the alkylated enzyme is hydrolysed by a water molecule activated by the His289-Asp260 pair in the active site. These results show that catalysis by the dehalogenase proceeds by a two-step mechanism involving an ester intermediate covalently bound at Asp124.

【 授权许可】

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