5CGS

CRYSTAL STRUCTURE OF Fox-4 cephamycinase

Summary for 5CGS

• Entry DOI: 10.2210/pdb5cgs/pdb
• Related: 5CGW 5CGX 5CHJ 5CHM
• Descriptor: Beta-lactamase, ZINC ION (3 entities in total)
• Functional Keywords: hydrolase
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 39069.43

Authors

Malashkevich, V.N.,Toro, R.,Lefurgy, S.,Almo, S.C. (deposition date: 2015-07-09, release date: 2016-02-03, Last modification date: 2023-09-27)

Primary citation

Lefurgy, S.T.,Malashkevich, V.N.,Aguilan, J.T.,Nieves, E.,Mundorff, E.C.,Biju, B.,Noel, M.A.,Toro, R.,Baiwir, D.,Papp-Wallace, K.M.,Almo, S.C.,Frere, J.M.,Bou, G.,Bonomo, R.A.
FOX-4 cephamycinase: an analysis of structure and function.
Antimicrob.Agents Chemother., 2015

PubMed Abstract: Class C β-lactamases poorly hydrolyze cephamycins (e.g., cefoxitin, cefotetan, and moxalactam). In the past 2 decades, a new family of plasmid-based AmpC β-lactamases conferring resistance to cefoxitin, the FOX family, has grown to include nine unique members descended from the Aeromonas caviae chromosomal AmpC. To understand the basis for the unique cephamycinase activity in the FOX family, we determined the first X-ray crystal structures of FOX-4, apo enzyme and the acyl-enzyme with its namesake compound, cefoxitin, using the Y150F deacylation-deficient variant. Notably, recombinant expression of N-terminally tagged FOX-4 also yielded an inactive adenylylated enzyme form not previously observed in β-lactamases. The posttranslational modification (PTM), which occurs on the active site Ser64, would not seem to provide a selective advantage, yet might present an opportunity for the design of novel antibacterial drugs. Substantial ligand-induced changes in the enzyme are seen in the acyl-enzyme complex, particularly the R2 loop and helix H10 (P289 to N297), with movement of F293 by 10.3 Å. Taken together, this study provides the first picture of this highly proficient class C cephamycinase, uncovers a novel PTM, and suggests a possible cephamycin resistance mechanism involving repositioning of the substrate due to the presence of S153P, N289P, and N346I substitutions in the ligand binding pocket.

PubMed: 26525784
DOI: 10.1128/AAC.01887-15

Experimental method

X-RAY DIFFRACTION (1.634 Å)