National Center for
2K1G: Solution NMR structure of lipoprotein spr from Escherichia coli K12. Northeast Structural Genomics target ER541-37-162
Solution NMR structure of the NlpC/P60 domain of lipoprotein Spr from Escherichia coli: structural evidence for a novel cysteine peptidase catalytic triad
Biochemistry (2008) 47 p.9715-9717
Escherichia coli Spr is a membrane-anchored cell wall hydrolase. The solution NMR structure of the C-terminal NlpC/P60 domain of E. coli Spr described here reveals that the protein adopts a papain-like alpha+beta fold and identifies a substrate-binding cleft featuring several highly conserved residues. The active site features a novel Cys-His-His catalytic triad that appears to be a unique structural signature of this cysteine peptidase family. Moreover, the relative orientation of these catalytic residues is similar to that observed in the analogous Ser-His-His triad, a variant of the classic Ser-His-Asp charge relay system, suggesting the convergent evolution of a catalytic mechanism in quite distinct peptidase families.