title: Structures and specificity of the human kallikrein-related peptidases KLK 4, 5, 6, and 7.
abstract: Human kallikrein-related peptidases (KLKs) are (chymo)-trypsin-like serine proteinases that are expressed in a variety of tissues such as prostate, ovary, breast, testis, brain, and skin. Although their physiological functions have been only partly elucidated, many of the KLKs appear to be useful prognostic cancer markers, showing distinct correlations between their expression levels and different stages of cancer. Recent advances in the purification of 'new type' recombinant KLKs allowed solution of the crystal structures of KLK4, KLK5, KLK6, and KLK7. Along with these data, enzyme kinetic studies and extended substrate specificity profiling have led to an understanding of the non-prime-side substrate preferences of KLK4, 5, 6, and 7. The shape and polarity of the specificity pockets S1-S4 explain well their substrate preferences. KLK4, 5, and 6 exhibit trypsin-like specificity, with a strong preference for Arg at the P1 position of substrates. In contrast, KLK7 displays a unique chymotrypsin-like specificity for Tyr, which is also preferred at P2. All four KLKs show little specificity for P3 residues and have a tendency to accept hydrophobic residues at P4. Interestingly, for KLK4, 5, and 7 extended charged surface regions were observed that most likely serve as exosites for physiological substrates.
authors.affiliation: Max-Planck-Institut für Biochemie, Proteinase Research Group, Am Klopferspitz 18, D-82152 Martinsried, Germany.
authors.forename: Mekdes
authors.initials: M
authors.lastname: Debela
authors.forename: Nathalie
authors.initials: N
authors.lastname: Beaufort
authors.forename: Viktor
authors.initials: V
authors.lastname: Magdolen
authors.forename: Norman M
authors.initials: NM
authors.lastname: Schechter
authors.forename: Charles S
authors.initials: CS
authors.lastname: Craik
authors.forename: Manfred
authors.initials: M
authors.lastname: Schmitt
authors.forename: Wolfram
authors.initials: W
authors.lastname: Bode
authors.forename: Peter
authors.initials: P
authors.lastname: Goettig
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007610:Kallikreins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity
chemical_list: D007610:Kallikreins