Abstract

Giardia lamblia is a food and waterborne parasite prevalent in developing countries, and a major cause of outbreaks of diarrhea in the United Sates, that has been classified as a bioterrorism category B organism by the Center for Disease Control because compromised water and food supply could affect US populations as well as army units in foreign countries. Drugs commonly used against anaerobic protozoa are used to treat giardiasis. However, they produce undesirable side effects, clinical resistance may occur in both immunocompromised and immunocompetent patients, and the rate of recurrence is high. The goal of this project is to develop new drug targets for alternative treatments of giardiasis. The sequence of the G. lamblia genome is available, thus, a genomic approach combined with biological insight has been taken to identify enzymes essential for the survival of the organism that are absent or are sufficiently divergent from the human enzymes to exploit those differences in the design of inhibitors. The selected enzymes will be cloned and expressed in E. coli using high throughput techniques, and those that are expressed in soluble form will be validated in G. lamblia by transcription interference methods. Essential enzymes will be prepared for structural and functional studies. Crystal structures will be determined, and will serve to guide the design of inhibitors specific to the Giardia enzymes. Assays to determine the kinetic constants of the enzymes will be developed and the catalytic mechanism will be studied to facilitate the in vitro evaluation of the inhibitors. Crystal structures of enzyme/inhibitor complexes will reveal how the inhibitor may be further improved. The effect of the inhibitors on the growth of G. lamblia will be determined. The long range goals of the project is to establish a database of potential drug targets against giardiasis, to gain insight about their mechanism of action, and to prepare inhibitors that are ready for preclinical evaluation.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI059733-05
Application #
7570087
Study Section
Special Emphasis Panel (ZRG1-IDM-N (90))
Program Officer
Rogers, Martin J
Project Start
2005-02-01
Project End
2010-09-14
Budget Start
2009-02-01
Budget End
2010-09-14
Support Year
5
Fiscal Year
2009
Total Cost
$568,876
Indirect Cost

  Institution

Name
University of MD Biotechnology Institute
Department
Type
Organized Research Units
DUNS #
603819210
City
Baltimore
State
MD
Country
United States
Zip Code
21202

  Publications

Zhao, Hong; Lim, Kap; Choudry, Anthony et al. (2012) Correlation of structure and function in the human hotdog-fold enzyme hTHEM4. Biochemistry 51:6490-2
Li, Zhimin; Liu, Zhengang; Cho, Dae Won et al. (2011) Rational design, synthesis and evaluation of first generation inhibitors of the Giardia lamblia fructose-1,6-biphosphate aldolase. J Inorg Biochem 105:509-17
Chen, Catherine Z; Kulakova, Liudmila; Southall, Noel et al. (2011) High-throughput Giardia lamblia viability assay using bioluminescent ATP content measurements. Antimicrob Agents Chemother 55:667-75
Galkin, Andrey; Kulakova, Liudmila; Wu, Rui et al. (2010) X-ray structure and characterization of carbamate kinase from the human parasite Giardia lamblia. Acta Crystallogr Sect F Struct Biol Cryst Commun 66:386-90
Galkin, Andrey; Li, Zhimin; Li, Ling et al. (2009) Structural insights into the substrate binding and stereoselectivity of giardia fructose-1,6-bisphosphate aldolase. Biochemistry 48:3186-96
Galkin, Andrey; Kulakova, Liudmila; Wu, Rui et al. (2009) X-ray structure and kinetic properties of ornithine transcarbamoylase from the human parasite Giardia lamblia. Proteins 76:1049-53
Li, Zhimin; Kulakova, Liudmila; Li, Ling et al. (2009) Mechanisms of catalysis and inhibition operative in the arginine deiminase from the human pathogen Giardia lamblia. Bioorg Chem 37:149-61
Li, Ling; Li, Zhimin; Chen, Danqi et al. (2008) Inactivation of microbial arginine deiminases by L-canavanine. J Am Chem Soc 130:1918-31
Li, Ling; Li, Zhimin; Wang, Canhui et al. (2008) The electrostatic driving force for nucleophilic catalysis in L-arginine deiminase: a combined experimental and theoretical study. Biochemistry 47:4721-32
Galkin, Andrey; Kulakova, Liudmila; Melamud, Eugene et al. (2007) Characterization, kinetics, and crystal structures of fructose-1,6-bisphosphate aldolase from the human parasite, Giardia lamblia. J Biol Chem 282:4859-67

Showing the most recent 10 out of 13 publications