Medical College of Wisconsin
CTSICores SearchResearch InformaticsREDCap

Conformational dynamics of metallo-β-lactamase CcrA during catalysis investigated by using DEER spectroscopy. J Biol Inorg Chem 2015 Apr;20(3):585-94

Date

04/02/2015

Pubmed ID

25827593

Pubmed Central ID

PMC4733638

DOI

10.1007/s00775-015-1244-8

Scopus ID

2-s2.0-84939954594 (requires institutional sign-in at Scopus site)   17 Citations

Abstract

Previous crystallographic and mutagenesis studies have implicated the role of a position-conserved hairpin loop in the metallo-β-lactamases in substrate binding and catalysis. In an effort to probe the motion of that loop during catalysis, rapid-freeze-quench double electron-electron resonance (RFQ-DEER) spectroscopy was used to interrogate metallo-β-lactamase CcrA, which had a spin label at position 49 on the loop and spin labels (at positions 82, 126, or 233) 20-35 Å away from residue 49, during catalysis. At 10 ms after mixing, the DEER spectra show distance increases of 7, 10, and 13 Å between the spin label at position 49 and the spin labels at positions 82, 126, and 233, respectively. In contrast to previous hypotheses, these data suggest that the loop moves nearly 10 Å away from the metal center during catalysis and that the loop does not clamp down on the substrate during catalysis. This study demonstrates that loop motion during catalysis can be interrogated on the millisecond time scale.

Author List

Aitha M, Moritz L, Sahu ID, Sanyurah O, Roche Z, McCarrick R, Lorigan GA, Bennett B, Crowder MW

Author

Brian Bennett D.Phil. Professor and Chair in the Physics department at Marquette University




MESH terms used to index this publication - Major topics in bold

Bacterial Proteins
Catalysis
Models, Molecular
Molecular Conformation
Molecular Dynamics Simulation
Spectrum Analysis
beta-Lactamases