3n5i
From Proteopedia
Crystal structure of the precursor (S250A mutant) of the N-terminal beta-aminopeptidase BapA
Structural highlights
FunctionBAPA_SPHXN Beta-aminopeptidase that can cleave synthetic beta-peptides which consist of backbone-elongated beta-amino acid residues that are not processed by common proteolytic enzymes. Can cleave the beta-peptides beta-homoVal-beta-homoAla-beta-homoLeu and beta-homoAla-beta-homoLeu. Requires a beta-amino acid at the N-terminus of peptide substrates and cleaves the peptide bond between the N-terminal beta-amino acid and the amino acid at the second position of tripeptidic substrates of the general structure H-betahXaa-Ile-betahTyr-OH according to the following preferences with regard to the side chain of the N-terminal beta-amino acid: aliphatic and aromatic > OH-containing > hydrogen, basic and polar.[1] [2] Publication Abstract from PubMedThe 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 (alphabeta)(4) heterooctamer and of the 153 kDa precursor homotetramer at a resolution of 1.45 and 1.8 A, 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. Autoproteolytic and catalytic mechanisms for the beta-aminopeptidase BapA--a member of the Ntn hydrolase family.,Merz T, Heck T, Geueke B, Mittl PR, Briand C, Seebach D, Kohler HP, Grutter MG Structure. 2012 Nov 7;20(11):1850-60. doi: 10.1016/j.str.2012.07.017. Epub 2012, Sep 12. PMID:22980995[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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