This proposal is focused on exploring the fundamental chemical mechanism of a large superfamily of enzymes called radical SAM enzymes. These enzymes occur in humans in such diverse functions as cofactor synthesis and the antiviral response, and are found in nature in all kingdoms of life. The radical SAM superfamily is large, with thousands of identified members catalyzing a range of reactions;they have in common the utilization of a specific type of metal cluster (a [4Fe-4S] cluster) and S-adenosyl-L-methionine (SAM) to initiate radical chemistry on their substrates. The current proposal will focus primarily on three members of the radical SAM superfamily (pyruvate formate-lyase activating enzyme, lysine 2,3-aminomutase, and viperin) that have diverse functions, and experiments will range from fundamental mechanistic, spectroscopic, and structural studies aimed at delineating details of the chemical mechanisms to basic functional studies aimed at understanding the role of an important mammalian radical SAM enzyme.
The specific aims of the proposal are: 1) To identify specific steps in the catalytic mechanisms of these enzymes by using techniques designed to trap reaction intermediates, 2) To explore valence localization in the [4Fe-4S] cluster of these enzymes, its causes, and its implications for function, 3) To structurally characterize the interaction between one radical SAM enzyme and its protein substrate, and 4) to functionally characterize a human radical SAM enzyme involved in the antiviral response.

Public Health Relevance

The proposed work will provide fundamental new insights into a class of enzymes that are widespread in nature. These enzymes participate in numerous processes relevant to public health, including the response of the human body to viral infections and the synthesis of essential vitamins.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM054608-16
Application #
8473222
Study Section
Macromolecular Structure and Function A Study Section (MSFA)
Program Officer
Anderson, Vernon
Project Start
1997-08-01
Project End
2015-05-31
Budget Start
2013-06-01
Budget End
2014-05-31
Support Year
16
Fiscal Year
2013
Total Cost
$253,611
Indirect Cost
$75,568
Name
Montana State University - Bozeman
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
625447982
City
Bozeman
State
MT
Country
United States
Zip Code
59717
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Ghose, Shourjo; Hilmer, Jonathan K; Bothner, Brian et al. (2014) Solution phase dynamics of the DNA repair enzyme spore photoproduct lyase as probed by H/D exchange. FEBS Lett 588:3023-9
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