RESEARCH OVERVIEW

Understanding Bacterial Response to Antibiotics

 Today, antimicrobial resistance continues to challenge any efforts made by the scientists in order to stay one step ahead of bacteria.  It is generally accepted that bacteria can rapidly acquire or become resistant to any chemotherapeutic agent.  Hence, we new strategies have to be designed in treating bacterial infections.  In our laboratory, we are focused at understanding the mechanisms of bacterial response to antibiotics stress and the function of antibiotic resistance factors.  In particular we are interested at the bacterial response to antibiotics that target bacterial cell wall biosynthesis.  Cell wall is essential to bacteria as it provides shape and mechanism strength to many of them.  In addition, because of its uniqueness to bacteria it has been a target for development of several classes of antibiotics, including beta-lactams and glycopeptides.  Development of resistance to these antibiotics has created a serious crisis in public health circles.

 The sequencing of the genomes of many pathogenic bacteria has allowed scientists to investigate the genome-wide response of bacteria to many antibiotics.  This response appears to be well coordinated by bacteria.  In Staphylococcus aureus scientists have shown that cell wall inhibiters of all stages of cell wall peptidoglycan induce similar genome-wide response.  Currently, we are investigating the role of a two-component system, VraSR in coordinating the response to cell wall stress.  In addition, we are investigating the function of several genes shown to have higher expression levels in the presence of cell wall inhibitors. 

 The research in Dr. Golemi-Kotra lab is multidisciplinary due to the nature of the biomolecules of interest and the interactions that they are engaged in bacteria.  As a result, the background of people that have joined the group in the past is quite diverse, from chemists to biologists.  In addition, our collaborators are also diverse providing complementary expertise in our group.

REPRESENTATIVE PUBLICATIONS

1. Belcheva, A. and Golemi-Kotra, D. A Close-Up View of the VraSR Two-Component System: A Mediator of Staphylococcus aureus Response to Cell Wall Damage. J. Biol. Chem. 2008, 283(18):12354-64.
2. Fan, X., Liu, Y-H., Smith, D. G. S., Siu, K. W. M., Konermann, L. and Golemi-Kotra, D. Diversity in Penicillin-Binding Proteins: Resistance Factor FmtA of Staphylococcus aureus. J. Biol. Chem. 2007, 282, 35143-52.
3. Holtzman, J., Woronowicz, K., Golemi-Kotra, D. and Schepartz, A. Miniature protein ligands for EVH1 domains: Interplay between affinity, specificity, and cell motility. Biochemistry  2007, 46, 13541-53.
4. Thomas V., Golemi-Kotra D., Kim, C., Vakulenko S. B., Mobashery S. and Shoichet B. The effect of S130G mutant in substrate and inhibitor spectrum of TEM-1 β-lactamase. Biochemistry, 2005, 44, 9330-38.
5. Golemi-Kotra D., Meroueh S. O., Kim C., Vakulenko S. B. Bulychev A., Stemmer A., Stemmer T. L. and Mobashery S. The importance of a critical protonation state and the fate of the catalytic steps in class A β-lactamases and penicillin binding proteins. J. Biol. Chem. 2004, 279, 34665-73.
6. Golemi-Kotra D., Mahaffy R., Footer M., Holtzman J., Pollard T., Theriot J. and Schepartz A. High affinity, paralog-specific recognition of the Mena EVH1 domain by a miniature protein ligand. J. Am. Chem. Soc. 2004, 126, 4-5.
7. Golemi-Kotra D., Young Cha J., Meroueh S. O., Vakulenko S. B. and Mobashery S. Resistance to β-lactam antibiotics and its mediation by the sensor domain of the transmembrane sensor-transducer signaling pathway in Staphylococcus aureus. J. Biol. Chem. 2003, 278, 18419-18425.
8. Meroueh S.O., Roblin P., Golemi D., Maveyraud L., Vakulenko S. B. Zhang Y., Samama J. P., Mobashery S. Molecular dynamics at the root of expansion of function in the M68L inhibitor-resistant TEM  β-lactamase from Escherichia coli. J. Am. Chem. Soc. 2002, 24, 9422-30.
9. Maveyraud L., Golemi D., Mobashery S., Samama J. P. High-resolution X ray structure of an acyl-enzyme species for the class D OXA-10 β-lactamase. J. Am. Chem. Soc. 2002, 124, 9422-30.
10. Vakulenko S. and Golemi D. Mutant TEM β-lactamase produsing resistance to ceftazidime, ampicillins and β-lactamase inhibitors. Antimicrob. Agents Chemother. 2002, 46, 646-53.
11. Vakulenko S., Golemi D., Geryk B., Souvorov M., Knox J., Mobashery S., Lerner S. Mutational replacement of Leu-293 in the class C Enterobacter cloacae P99 β-lactamase confers increased MIC of cefepime. Antimicrob. Agents Chemother. 2002, 46, 1966-70.
12. Golemi D., Maveyraud L., Vakulenko S., Tranier S., Samama J. P., Mobashery S. Critical involvement of carbamylated lysine in catalytic function of class D β-lactamases. Proc. Natl. Acad. Sci. USA. 2001, 98, 14280-5.
13. Nagase T., Golemi D., Ishiwata A., Mobashery S. Inhibition of β-lactamases by 6,6-bis(hydroxymethyl)penicillanate. Bioorg. Chem. 2001, 29, 140-5.
14. Maveyraud L., Golemi D., Vakulenko S., Tranier S., Ishiwata A., Kotra L. P., Mobashery S., Samama J. P. Insights into the class D β-lactamases are revealed by the crystal structure of the OXA-10 enzyme in Pseudomonas aeruginosa. Structure. 2000, 8, 1289-98.
15. Golemi D., Maveyraud L., Vakulenko S., Tranier S., Ishiwata A., Kotra L. P., Samama J. P., Mobashery S. The first structural and mechanistic insights for class D β-lactamases: Evidence for a novel catalytic process for turnover of β-lactam antibiotics. J. Am. Chem. Soc. 2000, 122, 6132-3.
16. Golemi D., Maveyraud L., Ishiwata A., Tranier S., Miyashita K., Nagase T., Massova I., Mourey L., Samama J. P., Mobashery S. 6-(xydroxyalkyl)penicillanates as probes for mechanisms of β-lactamases. J. Antibiot. 2000, 53, 1022-7.
17. Kotra L. P., Golemi D., Amro N. A., Liu G. Y., Mobashery S. Dynamics of the lipopolysaccharide assembly on the surface of Escherichia coli. J. Am. Chem. Soc. 1999, 21, 8707-11.
18. Swaren P., Golemi D., Cabantous S., Bulychev A., Maveyraud L., Mobashery S., Samama J. P. X-ray structure of the Asn276Asp variant of Escherichia coli TEM-1 β-lactamase: Direct observation of electrostatic modulation in resistance to inactivation by clavulanic acid. Biochemistry, 1999, 38, 9570-6.