Download MendeleyA Noncanonical Metal Center Drives the Activity of the Sediminispirochaeta smaragdinae Metallo-beta-lactamase SPS-1.
Cheng, Z., VanPelt, J., Bergstrom, A., Bethel, C., Katko, A., Miller, C., Mason, K., Cumming, E., Zhang, H., Kimble, R.L., Fullington, S., Bretz, S.L., Nix, J.C., Bonomo, R.A., Tierney, D.L., Page, R.C., Crowder, M.W.(2018) Biochemistry 57: 5218-5229
- PubMed: 30106565
- DOI: https://doi.org/10.1021/acs.biochem.8b00728
- Primary Citation of Related Structures:
6CQS - PubMed Abstract:
In an effort to evaluate whether a recently reported putative metallo-β-lactamase (MβL) contains a novel MβL active site, SPS-1 from Sediminispirochaeta smaragdinae was overexpressed, purified, and characterized using spectroscopic and crystallographic studies. Metal analyses demonstrate that recombinant SPS-1 binds nearly 2 equiv of Zn(II), and steady-state kinetic studies show that the enzyme hydrolyzes carbapenems and certain cephalosporins but not β-lactam substrates with bulky substituents at the 6/7 position. Spectroscopic studies of Co(II)-substituted SPS-1 suggest a novel metal center in SPS-1, with a reduced level of spin coupling between the metal ions and a novel Zn 1 metal binding site. This site was confirmed with a crystal structure of the enzyme. The structure shows a Zn 2 site that is similar to that in NDM-1 and other subclass B1 MβLs; however, the Zn 1 metal ion is coordinated by two histidine residues and a water molecule, which is held in position by a hydrogen bond network. The Zn 1 metal is displaced nearly 1 Å from the position reported in other MβLs. The structure also shows extended helices above the active site, which create a binding pocket that precludes the binding of substrates with large, bulky substituents at the 6/7 position of β-lactam antibiotics. This study reveals a novel metal binding site in MβLs and suggests that the targeting of metal binding sites in MβLs with inhibitors is now more challenging with the identification of this new MβL.
- Department of Chemistry and Biochemistry , Miami University , 651 East High Street, 160 Hughes Laboratories , Oxford , Ohio 45056 , United States.
Organizational Affiliation:
