Autoproteolytic and Catalytic Mechanisms for the beta-Aminopeptidase BapA-A Member of the Ntn Hydrolase Family

作者：Merz Tobias; Heck Tobias; Geueke Birgit; Mittl Peer R E; Briand Christophe; Seebach Dieter; Kohler Hans Peter E; Gruetter Markus G

来源：Structure, 2012, 20(11): 1850-1860.

DOI：10.1016/j.str.2012.07.017

The beta-aminopeptidase BapA from Sphingosinicella xenopeptidilytica belongs to the N-terminal nucleophile (Ntn) hydrolases of the DmpA-like family and has the unprecedented property of cleaving N-terminal beta-amino acid residues from peptides. We determined the crystal structures of the native (alpha beta)(4) heterooctamer and of the 153 kDa precursor homotetramer at a resolution of 1.45 and 1.8 angstrom, respectively. These structures together with mutational analyses strongly support mechanisms for autoproteolysis and catalysis that involve residues Ser250, Ser288, and Glu290. The autoproteolytic mechanism is different from the one so far described for Ntn hydrolases. The structures together with functional data also provide insight into the discriminating features of the active site cleft that determine substrate specificity.

• 出版日期2012-11-7