1cr6

Publication Abstract from PubMed

The crystal structure of recombinant murine liver cytosolic epoxide hydrolase (EC 3.3.2.3) has been determined at 2.8-A resolution. The binding of a nanomolar affinity inhibitor confirms the active site location in the C-terminal domain; this domain is similar to that of haloalkane dehalogenase and shares the alpha/beta hydrolase fold. A structure-based mechanism is proposed that illuminates the unique chemical strategy for the activation of endogenous and man-made epoxide substrates for hydrolysis and detoxification. Surprisingly, a vestigial active site is found in the N-terminal domain similar to that of another enzyme of halocarbon metabolism, haloacid dehalogenase. Although the vestigial active site does not participate in epoxide hydrolysis, the vestigial domain plays a critical structural role by stabilizing the dimer in a distinctive domain-swapped architecture. Given the genetic and structural relationships among these enzymes of xenobiotic metabolism, a structure-based evolutionary sequence is postulated.

Detoxification of environmental mutagens and carcinogens: structure, mechanism, and evolution of liver epoxide hydrolase.,Argiriadi MA, Morisseau C, Hammock BD, Christianson DW Proc Natl Acad Sci U S A. 1999 Sep 14;96(19):10637-42. PMID:10485878^[1]

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