In this competing continuation, mycobacterial cell wall metabolism is targeted as a route to new tuberculosis drugs. In one approach, essential cell wall biosynthetic enzymes are targetted. It is proposed to prepare M. tuberculosis luciferase reporter strains that respond specifically to inhibitors of the following essential enzymes: rhamnosyl transferase (WbbL), galactofuranosyl transferase (GlfT), dTDP-Rha formation enzymes (RmIB-D), and the UDP-Galf formation enzyme (Glf). In addition, direct enzyme assays amenable to screening for inhibitors will be developed for WbbL and GlfT (such assays are already in place for RmIB-D and Glf). It is further proposed to identify the genes encoding the three enzymes that form the arabinosyl donor, decaprenylphosphoryl-D-arabinose, show that their corresponding enzymes are essential, and prepare M. tuberculosis luciferase reporter strains and enzyme assays for use in finding inhibitors of them. In the second approach it is hypothesized that compounds that activate or deregulate the cell wall degrading arabinases and peptidoglycan hydrolyases can act more quickly than inhibition based drugs and thereby shorten tuberculosis therapy. Thus newly discovered M. tuberculosis endogenous arabinanases (of unknown function) that cleave cell wall arabinan will be purified and their genes identified. The effect of overexpressing these enzymes in M. tuberculosis will be tested; it is hoped the effect will be lethal. Reporter strains of M. tuberculosis to detect small molecules that up regulate the expression of the arabinanases will be prepared. The presence of a cell wall metabolic enzyme complex containing these arabinases (which can potentially be disrupted for therapy) will be searched for using a novel cross-linking reagent, cyanogen complexes of peptidoglycan synthetic and degradative enzymes, after covalent crosslinking with cyanogen, will be isolated. The identity of all proteins present in the complex will be determined by LC/MS and how individual proteins interact in the complex will be determined for the long-term goal of disrupting the complex to release the peptidoglycan cleaving enzymes. We will test M. tuberculosis for increased arabinase activity after exposure to novel highly active ethambutol like compounds (the presence of endogenous arabinase was first recognized during ethambutol treatment). Finally, large numbers of novel Betalactams will be tested for their action against M. tuberculosis with and without ethambutol like compounds anticipating that some will strongly stimulate cell wail degradation and bacterial death.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI033706-14
Application #
6930611
Study Section
Special Emphasis Panel (ZRG1-SSS-K (10))
Program Officer
Sizemore, Christine F
Project Start
1992-09-30
Project End
2007-08-31
Budget Start
2005-09-01
Budget End
2006-08-31
Support Year
14
Fiscal Year
2005
Total Cost
$391,446
Indirect Cost
Name
Colorado State University-Fort Collins
Department
Microbiology/Immun/Virology
Type
Schools of Veterinary Medicine
DUNS #
785979618
City
Fort Collins
State
CO
Country
United States
Zip Code
80523
Mahapatra, Sebabrata; Piechota, Charles; Gil, Filipa et al. (2013) Mycobacteriophage Ms6 LysA: a peptidoglycan amidase and a useful analytical tool. Appl Environ Microbiol 79:768-73
Bhamidi, Suresh; Scherman, Michael S; Jones, Victoria et al. (2011) Detailed structural and quantitative analysis reveals the spatial organization of the cell walls of in vivo grown Mycobacterium leprae and in vitro grown Mycobacterium tuberculosis. J Biol Chem 286:23168-77
Gil, Filipa; Grzegorzewicz, Anna E; Catalão, Maria João et al. (2010) Mycobacteriophage Ms6 LysB specifically targets the outer membrane of Mycobacterium smegmatis. Microbiology 156:1497-504
Birch, Helen L; Alderwick, Luke J; Rittmann, Doris et al. (2009) Identification of a terminal rhamnopyranosyltransferase (RptA) involved in Corynebacterium glutamicum cell wall biosynthesis. J Bacteriol 191:4879-87
Mahapatra, Sebabrata; Crick, Dean C; McNeil, Michael R et al. (2008) Unique structural features of the peptidoglycan of Mycobacterium leprae. J Bacteriol 190:655-61
Grzegorzewicz, Anna E; Ma, Yufang; Jones, Victoria et al. (2008) Development of a microtitre plate-based assay for lipid-linked glycosyltransferase products using the mycobacterial cell wall rhamnosyltransferase WbbL. Microbiology 154:3724-30
Meniche, Xavier; de Sousa-d'Auria, Celia; Van-der-Rest, Benoit et al. (2008) Partial redundancy in the synthesis of the D-arabinose incorporated in the cell wall arabinan of Corynebacterineae. Microbiology 154:2315-26
Bhamidi, Suresh; Scherman, Michael S; Rithner, Christopher D et al. (2008) The identification and location of succinyl residues and the characterization of the interior arabinan region allow for a model of the complete primary structure of Mycobacterium tuberculosis mycolyl arabinogalactan. J Biol Chem 283:12992-3000
Huang, Hairong; Berg, Stefan; Spencer, John S et al. (2008) Identification of amino acids and domains required for catalytic activity of DPPR synthase, a cell wall biosynthetic enzyme of Mycobacterium tuberculosis. Microbiology 154:736-43
Zhang, Wenli; Jones, Victoria C; Scherman, Michael S et al. (2008) Expression, essentiality, and a microtiter plate assay for mycobacterial GlmU, the bifunctional glucosamine-1-phosphate acetyltransferase and N-acetylglucosamine-1-phosphate uridyltransferase. Int J Biochem Cell Biol 40:2560-71

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