1keh

Precursor structure of cephalosporin acylasePrecursor structure of cephalosporin acylase

Structural highlights 1keh is a 1 chain structure with sequence from Brevundimonas diminuta. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.5Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function G7AC_BREDI Catalyzes the deacylation of 7 beta-(4-carboxybutanamido)cephalosporanic acid (glutaryl-7-aminocephalosporanic acid or GL-7-ACA) to 7-aminocephalosporanic acid (7-ACA). Can not efficiently use cephalosporin C (CPC), penicillin G, or ampicillin as substrates. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Autocatalytic proteolytic cleavage is a frequently observed post-translational modification in proteins. Cephalosporin acylase (CA) is a recently identified member of the N-terminal hydrolase family that is activated from an inactive precursor by autoproteolytic processing, generating a new N-terminal residue, which is either a Ser or a Thr. The N-terminal Ser or Thr becomes a nucleophilic catalytic center for intramolecular and intermolecular amide cleavages. The gene structure of the open reading frame of CAs generally consists of a signal peptide followed by the alpha-subunit, a spacer sequence, and the beta-subunit, which are all translated into a single polypeptide chain, the CA precursor. The precursor is post-translationally modified into an active heterodimeric enzyme with alpha- and beta-subunits, first by intramolecular cleavage and second by intermolecular cleavage. We solved the first CA precursor structure (code 1KEH) from a class I CA from Pseudomonas diminuta at a 2.5-A resolution that provides insight into the mechanism of intramolecular cleavage. A conserved water molecule, stabilized by four hydrogen bonds in unusual pseudotetrahedral geometry, plays a key role to assist the OG atom of Ser(1beta) to generate a strong nucleophile. In addition, the site of the secondary intermolecular cleavage of CA is proposed to be the carbonyl carbon of Gly(158alpha) (Kim, S., and Kim, Y., (2001) J. Biol. Chem., 276, 48376-48381), which is different from the situation in two other class I CAs. Precursor structure of cephalosporin acylase. Insights into autoproteolytic activation in a new N-terminal hydrolase family.,Kim Y, Kim S, Earnest TN, Hol WG J Biol Chem. 2002 Jan 25;277(4):2823-9. Epub 2001 Nov 8. PMID:11706000 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cephalosporin acylase 3D structures

spinqualitylabelsall models 1keh, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image