M1 aminopeptidases comprise a large family of biologically important zinc enzymes. We show that peptide turnover by the M1 prototype, leukotriene A4 hydrolase/aminopeptidase, involves a shift in substrate position associated with exchange of zinc coordinating groups, while maintaining the overall coordination geometry ...
M1 aminopeptidases comprise a large family of biologically important zinc enzymes. We show that peptide turnover by the M1 prototype, leukotriene A4 hydrolase/aminopeptidase, involves a shift in substrate position associated with exchange of zinc coordinating groups, while maintaining the overall coordination geometry. The transition state is stabilized by residues conserved among M1 members and in the final reaction step, Glu-296 of the canonical zinc binding HEXXH motif shuffles a proton from the hydrolytic water to the leaving group. Tripeptide substrates bind along the conserved GXMEN motif, precisely occupying the distance between Glu-271 and Arg-563, whereas the Arg specificity is governed by a narrow S1 pocket capped with Asp-375. Our data provide detailed insights to the active site chemistry of M1 aminopeptidases and will aid in the development of novel enzyme inhibitors.
Related Citations:
Assay for rapid analysis of the tri-peptidase activity of LTA4 hydrolase. Tholander, F., Haeggstrom, J.Z. (2007) Proteins 67: 1113
Leukotriene A4 hydrolase: identification of a common carboxylate recognition site for the epoxide hydrolase and aminopeptidase substrates. Rudberg, P.C., Tholander, F., Andberg, M., Thunnissen, M.M., Haeggstrom, J.Z. (2004) J Biol Chem 279: 27376
Leukotriene A4 hydrolase/aminopeptidase. Glutamate 271 is a catalytic residue with specific roles in two distinct enzyme mechanisms. Rudberg, P.C., Tholander, F., Thunnissen, M.M., Haeggstrom, J.Z. (2002) J Biol Chem 277: 1398
Leukotriene A4 hydrolase: selective abrogation of leukotriene B4 formation by mutation of aspartic acid 375. Rudberg, P.C., Tholander, F., Thunnissen, M.M., Samuelsson, B., Haeggstrom, J.Z. (2002) Proc Natl Acad Sci U S A 99: 4215
Crystal structure of human leukotriene A(4) hydrolase, a bifunctional enzyme in inflammation. Thunnissen, M.M., Nordlund, P., Haeggstrom, J.Z. (2001) Nat Struct Biol 8: 131
Organizational Affiliation:
Department of Medical Biochemistry and Biophysics, Division of Chemistry II, Karolinska Institute, Stockholm, Sweden.
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