Aertgeerts_2005_J.Biol.Chem_280_19441

Reference

Title : Structural and kinetic analysis of the substrate specificity of human fibroblast activation protein alpha - Aertgeerts_2005_J.Biol.Chem_280_19441
Author(s) : Aertgeerts K , Levin I , Shi L , Snell GP , Jennings A , Prasad GS , Zhang Y , Kraus ML , Salakian S , Sridhar V , Wijnands R , Tennant MG
Ref : Journal of Biological Chemistry , 280 :19441 , 2005
Abstract :

Fibroblast activation protein alpha (FAPalpha) is highly expressed in epithelial cancers and has been implicated in extracellular matrix remodeling, tumor growth, and metastasis. We present the first high resolution structure for the apoenzyme as well as kinetic data toward small dipeptide substrates. FAPalpha exhibits a dipeptidyl peptidase IV (DPPIV)-like fold, featuring an alpha/beta-hydrolase domain and an eight-bladed beta-propeller domain. Known DPPIV dipeptides are cleaved by FAPalpha with an approximately 100-fold decrease in catalytic efficiency compared with DPPIV. Moreover, FAPalpha, but not DPPIV, possesses endopeptidase activity toward N-terminal benzyloxycarbonyl (Z)-blocked peptides. Comparison of the crystal structures of FAPalpha and DPPIV revealed one major difference in the vicinity of the Glu motif (Glu(203)-Glu(204) for FAPalpha; Glu(205)-Glu(206) for DPPIV) within the active site of the enzyme. Ala(657) in FAPalpha, instead of Asp(663) as in DP-PIV, reduces the acidity in this pocket, and this change could explain the lower affinity for N-terminal amines by FAPalpha. This hypothesis was tested by kinetic analysis of the mutant FAPalpha/A657D, which shows on average an approximately 60-fold increase in the catalytic efficiency, as measured by k(cat)/K(m), for the cleavage of dipeptide substrates. Furthermore, the catalytic efficiency of the mutant is reduced by approximately 350-fold for cleavage of Z-Gly-Pro-7-amino-4-methylcoumarin. Our data provide a clear understanding of the molecular determinants responsible for the substrate specificity and endopeptidase activity of FAPalpha.

PubMedSearch : Aertgeerts_2005_J.Biol.Chem_280_19441
PubMedID: 15809306
Gene_locus related to this paper: human-FAP

Related information

Gene_locus human-FAP
Structure human-FAP    1Z68

Citations formats

Aertgeerts K, Levin I, Shi L, Snell GP, Jennings A, Prasad GS, Zhang Y, Kraus ML, Salakian S, Sridhar V, Wijnands R, Tennant MG (2005)
Structural and kinetic analysis of the substrate specificity of human fibroblast activation protein alpha
Journal of Biological Chemistry 280 :19441

Aertgeerts K, Levin I, Shi L, Snell GP, Jennings A, Prasad GS, Zhang Y, Kraus ML, Salakian S, Sridhar V, Wijnands R, Tennant MG (2005)
Journal of Biological Chemistry 280 :19441