PDBsum entry 1kvm

Hydrolase

PDB id: 1kvm

Contents

Protein chains

354 a.a. *

Ligands

PO4

CEO

Waters ×339

* Residue conservation analysis

PDB id:

1kvm

Name:

Hydrolase

Title:

X-ray crystal structure of ampc wt beta-lactamase in complex with covalently bound cephalothin

Structure:

Beta-lactamase. Chain: a, b. Synonym: cephalosporinase. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 562. Gene: k12. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.06Å R-factor: 0.176 R-free: 0.219

Authors:

B.M.Beadle,I.Trehan,P.J.Focia,B.K.Shoichet

Key ref:

B.M.Beadle et al. (2002). Structural milestones in the reaction pathway of an amide hydrolase: substrate, acyl, and product complexes of cephalothin with AmpC beta-lactamase. Structure, 10, 413-424. PubMed id: 12005439 DOI: 10.1016/S0969-2126(02)00725-6

Date:

27-Jan-02 Release date: 13-Mar-02

Protein chains

P00811  (AMPC_ECOLI) -  Beta-lactamase from Escherichia coli (strain K12)

Seq: 377 a.a.

Struc: 354 a.a.

Enzyme reactions

• Enzyme class: E.C.3.5.2.6 - beta-lactamase.
• Pathway: Penicillin Biosynthesis and Metabolism
• Reaction: a beta-lactam + H2O = a substituted beta-amino acid
• Cofactor: Zn(2+)

DOI no: 10.1016/S0969-2126(02)00725-6

Structure 10:413-424 (2002)

PubMed id: 12005439

Structural milestones in the reaction pathway of an amide hydrolase: substrate, acyl, and product complexes of cephalothin with AmpC beta-lactamase.

B.M.Beadle, I.Trehan, P.J.Focia, B.K.Shoichet.

ABSTRACT

Beta-lactamases hydrolyze beta-lactam antibiotics and are the leading cause of bacterial resistance to these drugs. Although beta-lactamases have been extensively studied, structures of the substrate-enzyme and product-enzyme complexes have proven elusive. Here, the structure of a mutant AmpC in complex with the beta-lactam cephalothin in its substrate and product forms was determined by X-ray crystallography to 1.53 A resolution. The acyl-enzyme intermediate between AmpC and cephalothin was determined to 2.06 A resolution. The ligand undergoes a dramatic conformational change as the reaction progresses, with the characteristic six-membered dihydrothiazine ring of cephalothin rotating by 109 degrees. These structures correspond to all three intermediates along the reaction path and provide insight into substrate recognition, catalysis, and product expulsion.

Selected figure(s)

Figure 3.
Figure 3. Stereoviews of Key Interactions Observed within Each Complexed Structure(A) S64G/cephalothin enzyme-substrate complex.(B) WT/cephalothin acyl complex.(C) S64G/cephalothin enzyme-product complex.Atoms are colored as in Figure 2, except that the carbon atoms of the substrate are green, the acyl ligand is orange, and the product is magenta, for clarity. Dashed yellow lines indicate interactions within hydrogen bonding distance; interaction distances are given in Table 2. Hydrogen bonds between protein residues are not shown. Figures 3 and 4 were generated using MidasPlus [53].

The above figure is reprinted by permission from Cell Press: Structure (2002, 10, 413-424) copyright 2002.

Figure was selected by an automated process.