The objective of this work is to investigate the structure, mechanism of action, and inhibition of three different types of metalloprotein, all of which utilize [4Fe-4S] clusters in catalysis. The reactions catalyzed are reductive dehydroxylations, dehydrations and isomerizations, and all of the proteins are of long-term interest because they are essential for the survival of many pathogens and are not used by humans. The proteins are IspG and IspH, involved in reductive dehydroxylations in isoprenoid biosynthesis; quinolinate synthase (NadA), involved in NAD biosynthesis; and dihydroxyacid dehydratase (DHAD) and isopropylmalate isomerase (LeuCD), involved in amino-acid biosynthesis.
In Aim 1 the first objective is to investigate a previously uncharacterized class of IspHs that are found in many anaerobic bacteria, such as those which cause tetanus and botulism, as well as many which are found in the human microbiome. These proteins are 2-3x larger than most bacterial IspHs and contain an IspH-RPS1 (ribosomal binding protein S1) fusion and might act as iron or oxygen sensors. The second objective is to probe the mechanisms of action of both IspG and IspH by using rapid freeze-quench EPR, calorimetry, site-directed mutagenesis, M?ssbauer, X-ray crystallography, and DFT to characterize reaction intermediates. The third objective is to determine the structures of the 3-domain IspGs and develop novel IspG inhibitors.
Aim 2 involves investigation of NadA, an enzyme whose apo-structure resembles that of IspH but whose structure with its 4Fe-4S cluster is unknown. The objective is to determine its structure and mechanism of action and to develop inhibitors as drug leads (against the organism that causes gastric ulcers and carcinoma).
The third Aim i nvolves two [4Fe-4S] hydratase/isomerases (DHAD and LeuCD). Both are predicted to contain two domains and it appears that there are structural similarities between DHAD, LeuCD, aconitase and fumarase A, a hypothesis we will test. Inhibitors have been reported as herbicides, blocking leucine and other branched chain amino-acid biosynthesis, an effect that with the LeuCD inhibitor is reversed with L- leucine, and M. tuberculosis leuCD knockouts are being developed as TB vaccines, making LeuCD and DHAD potential new drug targets and here, we will develop inhibitors, active in cells, that bind to their [4Fe-4S] clusters.

Public Health Relevance

The project is aimed at understanding the structure and function of a series of metallo-proteins that contain [4Fe-4S] clusters. These proteins are essential for the growth and survival of the organisms that cause tuberculosis, stomach ulcers and malaria but are not used by humans, making them of particular interest as drug targets.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM065307-16
Application #
9333380
Study Section
Macromolecular Structure and Function A Study Section (MSFA)
Program Officer
Anderson, Vernon
Project Start
2002-06-01
Project End
2018-08-31
Budget Start
2017-09-01
Budget End
2018-08-31
Support Year
16
Fiscal Year
2017
Total Cost
Indirect Cost
Name
University of Illinois Urbana-Champaign
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
041544081
City
Champaign
State
IL
Country
United States
Zip Code
61820
Rao, Guodong; Bansal, Sandhya; Law, Wen Xuan et al. (2017) Pulsed Electron Paramagnetic Resonance Insights into the Ligand Environment of Copper in Drosophila Lysyl Oxidase. Biochemistry 56:3770-3779
O'Dowd, Bing; Williams, Sarah; Wang, Hongxin et al. (2017) Spectroscopic and Computational Investigations of Ligand Binding to IspH: Discovery of Non-diphosphate Inhibitors. Chembiochem 18:914-920
Mohammad, Haroon; Younis, Waleed; Chen, Lu et al. (2017) Phenylthiazole Antibacterial Agents Targeting Cell Wall Synthesis Exhibit Potent Activity in Vitro and in Vivo against Vancomycin-Resistant Enterococci. J Med Chem 60:2425-2438
Boulmier, Amandine; Feng, Xinxin; Oms, Olivier et al. (2017) Anticancer Activity of Polyoxometalate-Bisphosphonate Complexes: Synthesis, Characterization, In Vitro and In Vivo Results. Inorg Chem 56:7558-7565
Schwalen, Christopher J; Feng, Xinxin; Liu, Weidong et al. (2017) Head-to-Head Prenyl Synthases in Pathogenic Bacteria. Chembiochem 18:985-991
Desai, Janish; Wang Dr, Yang; Wang Dr, Ke et al. (2016) Isoprenoid Biosynthesis Inhibitors Targeting Bacterial Cell Growth. ChemMedChem 11:2205-2215
Rao, Guodong; Oldfield, Eric (2016) Structure and Function of Four Classes of the 4Fe-4S Protein, IspH. Biochemistry 55:4119-29
Desai, Janish; Liu, Yi-Liang; Wei, Hongli et al. (2016) Structure, Function, and Inhibition of Staphylococcus aureus Heptaprenyl Diphosphate Synthase. ChemMedChem 11:1915-23
García-García, Verónica; Oldfield, Eric; Benaim, Gustavo (2016) Inhibition of Leishmania mexicana Growth by the Tuberculosis Drug SQ109. Antimicrob Agents Chemother 60:6386-9
Li, Jikun; Feng, Xinxin; Zhu, Wei et al. (2016) Chemical Exchange Saturation Transfer (CEST) Agents: Quantum Chemistry and MRI. Chemistry 22:264-71

Showing the most recent 10 out of 93 publications