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SPECTROSCOPIC STUDIES ON ACTIVE METALLO-ß-LACTAMASES

Aitha, Mahesh Kumar
http://orcid.org/0000-0003-0377-4792
http://rave.ohiolink.edu/etdc/view?acc_num=miami1440671336

Abstract Details

2015, Doctor of Philosophy, Miami University, Chemistry and Biochemistry.
Antibiotic resistance is a major challenge in the treatment of bacterial infections. According to a Centers for Disease Control report in 2013, more than two million people were affected by antibiotic resistance in 2012 and more than 23,000 people in the United States died. Zinc-dependent metallo-ß-lactamases (MBLs) are an emerging class of enzymes that render bacteria resistant to most ß-lactam containing antibiotics, such as penicillins, cephalosporins, and carbapenems. It is essential to understand the catalytic mechanism of these enzymes to design effective inhibitors, which could be given in combination with existing antibiotics to combat antibiotic resistant bacterial infections. To better understand the role(s) of the zinc ions in the active sites of these enzymes, several MBLs were characterized using kinetic, crystallographic, and spectroscopic studies. Our results demonstrated the first successful preparation of a Co(II)-substituted analog of MBL VIM-2, which allowed for a better understanding of zinc binding to VIM-2 and how VIM-2 is different from other MBLs. The roles of the metal binding sites in MBL L1 were investigated by using rapid freeze quench Extended X-ray Absorption Fine Structure spectroscopic studies on an analog of L1 that binds zinc in one metal binding site and cobalt in the other site. To understand the role of an invariant hairpin loop in most MBLs, rapid-freeze quench Double Electron Electron Resonance spectroscopy was used to measure the distances between site-specifically introduced sping label in MBLs L1, CcrA, and NDM-1 as the enzymes hydrolyzed substrate. Our results showed that the hairpin loop is crucial for the catalysis and that the loop undergoes large movements during catalysis. The results in this dissertation will be used to guide future inhibitor design efforts on MBLs.
Michael Crowder, Dr. (Advisor)
David Tierney, Dr. (Committee Chair)
Christopher Makaroff, Dr. (Committee Member)
Richard Page, Dr. (Committee Member)
James Moller, Dr. (Committee Member)
226 p.
Biochemistry; Chemistry; Inorganic Chemistry; Physical Chemistry
Metallo-beta-lactamases; beta-lactam antibiotics; Rapid-freeze quench; Extended X-ray Absorption Fine Structure; Double Electron Electron Resonance spectroscopy; VIM-2; L1; CcrA; NDM-1; Hairpin loop

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Citations

  • Aitha, M. K. (2015). SPECTROSCOPIC STUDIES ON ACTIVE METALLO-ß-LACTAMASES [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1440671336

    APA Style (7th edition)

  • Aitha, Mahesh Kumar. SPECTROSCOPIC STUDIES ON ACTIVE METALLO-ß-LACTAMASES. 2015. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1440671336.

    MLA Style (8th edition)

  • Aitha, Mahesh Kumar. "SPECTROSCOPIC STUDIES ON ACTIVE METALLO-ß-LACTAMASES." Doctoral dissertation, Miami University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=miami1440671336

    Chicago Manual of Style (17th edition)

miami1440671336
749
© 2015, all rights reserved.
This open access ETD is published by Miami University and OhioLINK.