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Chan H, Pearson CS, Green CM, Li Z, Zhang J, Belfort G, Shekhtman A, Li H, Belfort M. Exploring Intein Inhibition by Platinum Compounds as an Antimicrobial Strategy. J Biol Chem 2016; 291:22661-22670. [PMID: 27609519 DOI: 10.1074/jbc.m116.747824] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/29/2016] [Indexed: 01/10/2023] Open
Abstract
Inteins, self-splicing protein elements, interrupt genes and proteins in many microbes, including the human pathogen Mycobacterium tuberculosis Using conserved catalytic nucleophiles at their N- and C-terminal splice junctions, inteins are able to excise out of precursor polypeptides. The splicing of the intein in the mycobacterial recombinase RecA is specifically inhibited by the widely used cancer therapeutic cisplatin, cis-[Pt(NH3)2Cl2], and this compound inhibits mycobacterial growth. Mass spectrometric and crystallographic studies of Pt(II) binding to the RecA intein revealed a complex in which two platinum atoms bind at N- and C-terminal catalytic cysteine residues. Kinetic analyses of NMR spectroscopic data support a two-step binding mechanism in which a Pt(II) first rapidly interacts reversibly at the N terminus followed by a slower, first order irreversible binding event involving both the N and C termini. Notably, the ligands of Pt(II) compounds that are required for chemotherapeutic efficacy and toxicity are no longer bound to the metal atom in the intein adduct. The lack of ammine ligands and need for phosphine represent a springboard for future design of platinum-based compounds targeting inteins. Because the intein splicing mechanism is conserved across a range of pathogenic microbes, developing these drugs could lead to novel, broad range antimicrobial agents.
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Affiliation(s)
- Hon Chan
- From the Department of Biological Sciences and RNA Institute and.,Howard P. Isermann Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - C Seth Pearson
- From the Department of Biological Sciences and RNA Institute and.,Howard P. Isermann Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Cathleen M Green
- From the Department of Biological Sciences and RNA Institute and
| | - Zhong Li
- Laboratory of Computational and Structural Biology, Wadsworth Center, New York State Department of Health, Albany, New York 12208, and
| | - Jing Zhang
- Laboratory of Computational and Structural Biology, Wadsworth Center, New York State Department of Health, Albany, New York 12208, and
| | - Georges Belfort
- Howard P. Isermann Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Alex Shekhtman
- Department of Chemistry, University at Albany, State University of New York, Albany, New York 12222
| | - Hongmin Li
- Laboratory of Computational and Structural Biology, Wadsworth Center, New York State Department of Health, Albany, New York 12208, and.,Department of Biomedical Sciences, University at Albany, State University of New York, Albany, New York 12201
| | - Marlene Belfort
- From the Department of Biological Sciences and RNA Institute and
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