Inducible Antibiotic Resistance in Methicillin-Resistant Staphylococcus Aureus

Summary

Principal Investigator: Shahriar Mobashery
Abstract: DESCRIPTION (provided by applicant): Methicillin-resistant Staphylococcus aureus (MRSA) has acquired an inducible resistance mechanism to [unreadable]- lactam antibiotics that encompasses essentially all members of the antibiotic class. This resistance is conferred by a set of genes that encode an antibiotic sensor/signal transducer protein, gene repressor and two resistant determinants, a class A [unreadable]-lactamases and a special penicillin-binding protein (PBP) referred to as PBP2a. We have documented that the antibiotic sensor/signal transducer protein BlaR1 experiences covalent modification by [unreadable]-lactam antibiotics in its membrane-surface domain, which through a unique process that we have termed "lysine N-decarboxylation switch" activates the protein for signal transduction across the membrane. Subsequent to this event, the cytoplasmic domain of BlaR1 experiences phosphorylation, all within the time frame relevant to induction of resistance. The elucidation of the importance of this BlaR1 phosphorylation to the antibiotic resistance events is the subject of study under Specific Aim 1. PBP2a performs cross-linking of the cell wall in MRSA, a function that is indispensible to its survival. PBP2a is not inhibited well by [unreadable]-lactam antibiotics as it has a closed active site, hence its function in resistance. We have elucidated an allosteric site on this protein that is triggered to facilitate opening of the active site for the physiological role of the protein. The allosteric site is an Achiles'Heel of PBP2a, since its triggering for the opening of the active site would leave the protein (and MRSA) vulnerable to [unreadable]-lactam antibiotics that have met their obsolescence in treatment of infections by MRSA. In Specific Aim 2 we propose to investigate how this protein performs its physiological role and how its processes can be subverted in devising new strategies in treatment of MRSA infections. Furthermore, we propose to study antibiotic resistance mechanisms that arise by alterations in the allosteric site.
Funding Period: 2013-01-01 - 2017-12-31
more information: NIH RePORT

Top Publications

  1. pmc How allosteric control of Staphylococcus aureus penicillin binding protein 2a enables methicillin resistance and physiological function
    Lisandro H Otero
    Departamento de Cristalografía y Biología Estructural, Instituto de Quimica Fisica Rocasolano, Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain
    Proc Natl Acad Sci U S A 110:16808-13. 2013
  2. pmc Revealing cell-surface intramolecular interactions in the BlaR1 protein of methicillin-resistant Staphylococcus aureus by NMR spectroscopy
    Thomas E Frederick
    The Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
    Biochemistry 53:10-2. 2014
  3. pmc Regulation of the expression of the β-lactam antibiotic-resistance determinants in methicillin-resistant Staphylococcus aureus (MRSA)
    Blas Blázquez
    Department Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
    Biochemistry 53:1548-50. 2014

Detail Information

Publications3

  1. pmc How allosteric control of Staphylococcus aureus penicillin binding protein 2a enables methicillin resistance and physiological function
    Lisandro H Otero
    Departamento de Cristalografía y Biología Estructural, Instituto de Quimica Fisica Rocasolano, Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain
    Proc Natl Acad Sci U S A 110:16808-13. 2013
    ....
  2. pmc Revealing cell-surface intramolecular interactions in the BlaR1 protein of methicillin-resistant Staphylococcus aureus by NMR spectroscopy
    Thomas E Frederick
    The Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
    Biochemistry 53:10-2. 2014
    ....
  3. pmc Regulation of the expression of the β-lactam antibiotic-resistance determinants in methicillin-resistant Staphylococcus aureus (MRSA)
    Blas Blázquez
    Department Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
    Biochemistry 53:1548-50. 2014
    ..Within the range of in vivo concentrations for BlaI and MecI, these proteins interact with their regulatory elements in a reversible manner, as both a monomer and a dimer...

Research Grants62

  1. Elucidating beta-lactamase functional mechanisms via evolutionary conservation
    Dennis R Livesay; Fiscal Year: 2013
    ..As such, we propose a series of additional studies along these lines to expand our understanding of BL structure and function, potentially paving the way to new therapeutic opportunities. ..
  2. Class A Carbapenemases
    Sergei Vakulenko; Fiscal Year: 2013
    ..Elucidation of the catalytic mechanisms and structures of class A carbapenemases has the potential to result in development of the next generations of ?-lactam antibiotics and inhibitors of these enzymes. ..
  3. Cell wall synthesis enzymes and beta-lactam resistance in Enterococcus faecium
    Louis B Rice; Fiscal Year: 2013
    ..They will also enhance our understanding of cell wall synthesis mechanisms in Gram-positive cocci and reveal promising new targets for antibacterial therapy. ..
  4. Molecular Targets in Peptidoglycan Synthesis
    Christopher Davies; Fiscal Year: 2013
    ..To understand the functional role of AmiC in peptidoglycan breakdown, but also to pave the way for drug discovery against its two active sites, we will obtain essential structural and biochemical information for AmiC. ..
  5. Structure, Function and Inhibition of Beta-lactamases
    Brian K Shoichet; Fiscal Year: 2013
    ..A second is to exploit this information to discover novel inhibitors to escape the current cycle of incremental antibiotic modification followed by rapid resistance response. ..
  6. BETA LACTAMASE MUTATIONS IN ANTIBIOTIC RESISTANCE
    Timothy Palzkill; Fiscal Year: 2013
    ..The proposed experiments will determine how amino acid substitutions in the sequence of ?-lactamase enzymes alter their structure, function and evolution, which will facilitate the design of new antimicrobial therapeutics. ..
  7. Pediatric toxicity and efficacy in long-term systemic treatment with anti-sense
    JOHANNES NICOLAAS VAN DEN ANKER; Fiscal Year: 2013
    ..A kidney toxicology assessment core supports these projects. ..
  8. Maturation of Bacterial Cell Wall
    Shahriar Mobashery; Fiscal Year: 2013
    ..The studies of the details of the functions of these enzymes are proposed. ..
  9. Novel Mechanisms of Beta-lactam Resistance in Staph Aureus
    Henry F Chambers; Fiscal Year: 2013
    ..Recombinant GdpP also will be purified and analyzed by x-ray crystallography to identify its critical structural properties. Achieving these aims will increase knowledge of ?-lactam antibiotic effects and mechanisms of resistance. ..
  10. Protein-protein interaction essential for bacterial growth and virulence
    Mark A Saper; Fiscal Year: 2013
    ..Moreover, the mode of ac- tion of such an inhibitor would be complementary with, but different from, ?-lactams. ..
  11. The bacterial mechanosentitive channel as a multimodal sensor device
    DAMIAN BRETT VAN ROSSUM; Fiscal Year: 2013
    ....
  12. GENETIC ANALYSIS OF PROTEIN EXPORT
    Thomas J Silhavy; Fiscal Year: 2013
    ..Multi-drug resistant Gram- negative bacteria are a growing concern. Insights obtained from this work should facilitate the design of novel antibacterial agents. ..
  13. Mucosal Cell Transporters and Enzymes for Enhancing Oral Drug Absorption
    Gordon L Amidon; Fiscal Year: 2013
    ..This will enable the development of new, more effective, drugs for treatment of viral infections. ..
  14. Meropenem Prodrugs for XDR-TB
    Rory P Remmel; Fiscal Year: 2013
    ..Efficacy studies will be conducted in a BSL-3 laboratory in the guinea pig model of TB. ..
  15. Roles of Phosphate Uptake in Pneumococcal Antibiotic Resistance and Virulence
    Malcolm E Winkler; Fiscal Year: 2013
    ....
  16. Enabling Biotechnologies to Generate Novel Phosphoglycolipid Antibiotics
    Suzanne Walker; Fiscal Year: 2013
    ..I. Suzanne Walker) of NIH Grant 2P01AI083214-04 (P.I. Michael Gilmore). ..
  17. MepRA, A Substrate-Responsive Repressor-MATE MDR Efflux Pump Tandem in S. aureus
    GLENN WILLIAM KAATZ; Fiscal Year: 2013
    ..aureus MDR pumps simultaneously. This will be an advance in antibacterial chemotherapy resulting in an improvement in patient outcomes, which is directly relevant to the mission of the VA. ..
  18. IMpact of PRObiotics for reducing infections in VEterans: The IMPROVE Study
    Nasia Safdar; Fiscal Year: 2013
    ..If found to be efficacious, probiotics represent an easily implementable, safe, and well-tolerated intervention that is suitable for use in a field environment and requires no special conditions for it to be used. ..
  19. The role of GraRS in resistance to cationic antimicrobial peptides in S. aureus
    AMBROSE LIN YAU CHEUNG; Fiscal Year: 2013
    ..We propose to define the mechanism of this resistance. Our long-term goal is to characterize these genes that confer sensitivity to cationic antimicrobial peptides so that we can design better peptide-based antibiotics in the future. ..
  20. BIOLOGICALLY ACTIVE CYCLIC PEPTIDES
    Dale L Boger; Fiscal Year: 2013
    ....
  21. Vaccine Assembly from Surface Proteins of Staphylococcus Aureus
    Olaf Schneewind; Fiscal Year: 2013
    ..abstract_text> ..
  22. Cell Surface Protein Anchoring and Function in Gram-Positive Bacteria
    ROBERT THOMPSON CLUBB; Fiscal Year: 2013
    ..Collectively, this research will increase our understanding of the molecular basis of S. aureus pathogenesis and it could lead to new therapeutics to treat bacterial infections. ..
  23. Southeast Regional Centers of Excellence for Biodefense &Emerging Infectious Di
    Philip Frederick Sparling; Fiscal Year: 2013
    ..SERCEB brings new investigators to the biodefense effort through a combination of educational programs, support of innovative new projects, and the synergistic interactions among its world-class investigators. ..
  24. Molecular Mechanisms Of Daptomycin Resistance In Enterococci
    CESAR AUGUSTO ARIAS; Fiscal Year: 2013
    ....
  25. Bioflavonoid Effects on EGF Signaling and Cell Cycle Pathways in Prostate Cancer
    BARRY MATTHEW MARKAVERICH; Fiscal Year: 2013
    ..These studies may lead to the development of new drugs and/or dietary components for use in cancer prevention or treatment. ..
  26. Molecular Archaeology: Vintage Beta Lactams for Resistant Gram Negative Infectio
    Marvin J Miller; Fiscal Year: 2013
    ..Conduct in vitro toxicology battery and pilot toxicology studies. Aim 5. Conduct 14-day range-finding toxicology studies. Upon successful completion of this project, we will be ready to proceed into IND-enabling toxicology studies. ..
  27. Regulation and specificity of deubiquitylating enzyme complex
    Zhihao Zhuang; Fiscal Year: 2013
    ..Further, our study will suggest new directions for pharmacologic intervention of this important class of human USPs. ..
  28. IkB/NF-kB Recognition In Silico, In Vitro and In Vivo
    Elizabeth A Komives; Fiscal Year: 2013
    ....
  29. Investigation into the antibiotic activity of the lantibiotic haloduracin
    Rebecca A Splain; Fiscal Year: 2013
    ..The results of this work will enhance the mechanistic understanding of lantibiotic bioactivity, which may guide the development of new antibacterial compounds. ..
  30. Antibiotic resistant genes and resistant phenotypes in MRSA and VISA strains
    Alexander Tomasz; Fiscal Year: 2013
    ....
  31. BIOSYNTHESIS OF BETA-LACTAM ANTIBIOTICS
    CRAIG ARTHUR TOWNSEND; Fiscal Year: 2013
    ..abstract_text> ..
  32. Photodynamic Therapy of Localized Infections
    Michael R Hamblin; Fiscal Year: 2013
    ....
  33. ESAT-6 Secretion in Staphylococcus Aureus
    Dominique M Missiakas; Fiscal Year: 2013
    ..Moreover, staphylococcal esxB mutants are interrogated for the genetic requirements of generating protective immunity against S. aureus disease. ..