The structure of aspartyl dipeptidase reveals a unique fold with a Ser-His-Glu catalytic triad.
The three-dimensional structure of Salmonella typhimurium aspartyl dipeptidase, peptidase E, was solved crystallographically and refined to 1.2-A resolution. The structure of this 25-kDa enzyme consists of two mixed beta-sheets forming a V, flanked by six alpha-helices. The active site contains a Ser-His-Glu catalytic triad and is the first example of a serine peptidase/protease with a glutamate in the catalytic triad. The active site Ser is located on a strand-helix motif reminiscent of that found in alpha/beta-hydrolases, but the polypeptide fold and the organization of the catalytic triad differ from those of the known serine proteases. This enzyme is a member of a family of serine hydrolases and appears to represent a new example of convergent evolution of peptidase activity.
Håkansson
K
K
Departments of Microbiology and Cell and Structural Biology, B103 Chemical and Life Science Laboratory, University of Illinois at Urbana-Champaign, 601 South Goodwin Avenue, Urbana, IL 61801, USA.
Wang
A H
AH
Miller
C G
CG
D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004150:Dipeptidases / Q000737:chemistry*; D018698:Glutamic Acid / Q000737:chemistry*; D006639:Histidine / Q000737:chemistry*; D008958:Models, Molecular; D017433:Protein Structure, Secondary; D012486:Salmonella typhimurium / Q000201:enzymology*; D012694:Serine / Q000737:chemistry*
D018698:Glutamic Acid; D012694:Serine; D006639:Histidine; D004150:Dipeptidases; C042430:aspartyl peptidase E