Survival of the bacterium depends on the health of its cell wall. Because of the indispensable nature of the cell wall, the biosynthetic enzymes of its assembly and the cell wall itself are targets of several of the existing antibiotics. The final steps of cell wall assembly and maturation are performed by a group of enzymes referred to as penicillin- binding proteins (PBPs) on the surface of the cytoplasmic membrane. As the name suggests, these enzymes are inhibited by beta-lactam antibiotics (e.g., penicillins), and they serve as validated targets for the bactericidal activity by these antibiotics. Despite their importance, many aspects of biochemistry of PBPs have not been investigated and there are currently no other known effective inhibitors for these enzymes. This project addresses this paucity of information within the scope of three Specific Aims.
Specific Aim 1 deals with PBPs with the DD-transpeptidase activity. These enzymes perform the important cross-linking reaction of the cell wall. The studies build on earlier work from the Mobashery lab in elucidation of the microscopic steps in the enzymic reaction, both by experiments and by computational analyses. The knowledge is applied to a strategy for mechanism-based inhibition of these enzymes.
Specific Aim 2 will address the mechanistic details of PBPs with the DD-carboxypeptidase activity by both experiments and computation. There enzymes process the cell wall hydrolytically, whereby they moderate the degree of cross-linking that is performed by DD-transpeptidases.
Specific Aim 3 addresses the catalytic mechanisms of bifunctional PBPs that possess the transglycosylase and DD-transpeptidase activities, explicitly exploring the cross-talk between the two active sites that would influence one another in biosynthesis of cell wall.
Penicillin-binding proteins (PBPs), targets of ?-lactam antibiotics (such as penicillin), are involved in maturation of cell wall, a set of critical functions that are important for the survival of bacteria. The studies of the details of the functions of these enzymes are proposed.
|Lee, Mijoon; Hesek, Dusan; Zají?ek, Jaroslav et al. (2017) Synthesis and shift-reagent-assisted full NMR assignment of bacterial (Z8,E2,?)-undecaprenol. Chem Commun (Camb) 53:12774-12777|
|Sandalova, Tatyana; Lee, Mijoon; Henriques-Normark, Birgitta et al. (2016) The crystal structure of the major pneumococcal autolysin LytA in complex with a large peptidoglycan fragment reveals the pivotal role of glycans for lytic activity. Mol Microbiol 101:954-67|
|Schaub, Ryan E; Chan, Yolande A; Lee, Mijoon et al. (2016) Lytic transglycosylases LtgA and LtgD perform distinct roles in remodeling, recycling and releasing peptidoglycan in Neisseria gonorrhoeae. Mol Microbiol 102:865-881|
|Lenz, Jonathan D; Stohl, Elizabeth A; Robertson, Rosanna M et al. (2016) Amidase Activity of AmiC Controls Cell Separation and Stem Peptide Release and Is Enhanced by NlpD in Neisseria gonorrhoeae. J Biol Chem 291:10916-33|
|An, Doo Ri; Im, Ha Na; Jang, Jun Young et al. (2016) Structural Basis of the Heterodimer Formation between Cell Shape-Determining Proteins Csd1 and Csd2 from Helicobacter pylori. PLoS One 11:e0164243|
|Turapov, Obolbek; Loraine, Jessica; Jenkins, Christopher H et al. (2015) The external PASTA domain of the essential serine/threonine protein kinase PknB regulates mycobacterial growth. Open Biol 5:150025|
|An, Doo Ri; Kim, Hyoun Sook; Kim, Jieun et al. (2015) Structure of Csd3 from Helicobacter pylori, a cell shape-determining metallopeptidase. Acta Crystallogr D Biol Crystallogr 71:675-86|
|Kim, Hyoun Sook; Im, Ha Na; An, Doo Ri et al. (2015) The Cell Shape-determining Csd6 Protein from Helicobacter pylori Constitutes a New Family of L,D-Carboxypeptidase. J Biol Chem 290:25103-17|
|Kim, Hyoun Sook; Kim, Jieun; Im, Ha Na et al. (2014) Structural basis for the recognition of muramyltripeptide by Helicobacter pylori Csd4, a D,L-carboxypeptidase controlling the helical cell shape. Acta Crystallogr D Biol Crystallogr 70:2800-12|
|Mellroth, Peter; Sandalova, Tatyana; Kikhney, Alexey et al. (2014) Structural and functional insights into peptidoglycan access for the lytic amidase LytA of Streptococcus pneumoniae. MBio 5:e01120-13|
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