The broad, long term goal of this research is to elucidate the role of conformational change in catalysis and enzyme regulation. Our research will emphasize the allosteric regulation and inter- and intramolecular communication of riboucleotide reductases (RNRs). These amazing enzymes utilize organic radical-based chemistry to convert nucleotides to deoxynucleotides. Allosteric regulation of RNR enzymes serves to maintain an appropriate supply of each of four deoxynucleotides (dNTPs) needed for DNA replication and repair. As a result of these cellular activities, RNRs are actively pursued as targets for antibacterial, antiviral, and antitumor therapies. Gemcitabine (2',2'-difluoro-2'-deoxycytidine), a mechanism-based inhibitor of RNRs, was recently approved by the FDA for treatment of pancreatic cancer and demonstrates the medical importance of these enzymes. The proposed research is intended to identify the conformational changes involved in RNR re-reduction by thioredoxin/thioredoxin reductase/NADPH, to identify the role of conformational change in the allosteric regulation of radical formation, and to identify the structural basis for allosteric regulation of enzyme specificity. These goals will be achieved by crystallographic analysis of the least complex members of the ribonucleotide reductase family, the B12-dependent class II enzymes. We will complement structural data with biochemical characterization and single crystal spectroscopic techniques.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM065337-05
Application #
7047931
Study Section
Biophysical Chemistry Study Section (BBCB)
Program Officer
Basavappa, Ravi
Project Start
2002-04-01
Project End
2009-03-31
Budget Start
2006-04-01
Budget End
2007-03-31
Support Year
5
Fiscal Year
2006
Total Cost
$307,055
Indirect Cost
Name
Massachusetts Institute of Technology
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
001425594
City
Cambridge
State
MA
Country
United States
Zip Code
02139
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Lingaraju, Gondichatnahalli M; Davis, C Ainsley; Setser, Jeremy W et al. (2011) Structural basis for the inhibition of human alkyladenine DNA glycosylase (AAG) by 3,N4-ethenocytosine-containing DNA. J Biol Chem 286:13205-13
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Ryan, Katherine S; Chakraborty, Sumita; Howard-Jones, Annaleise R et al. (2008) The FAD cofactor of RebC shifts to an IN conformation upon flavin reduction. Biochemistry 47:13506-13

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