Coenzyme B12 (aka, adenosylcobalamin, AdoCbl) is synthesized only by prokaryotes, and is essential to the survival of many pathogens. Hence, precise knowledge of the biochemistry underpinning this major pathway (~25 reactions), and an understanding of the structural properties of the enzymes involved, is critical to the design of inhibitors that could be used to target disease-causing bacteria or any other prokaryote of societal importance. I will apply a multidisciplinary approach to study the last step of AdoCbl biosynthesis, which is catalyzed by the AdoCbl-P phosphatase (CobC) enzyme. There are two parts to my proposal: i) Functional and topological studies of CobC;ii) analysis of interactions of CobC with other proteins suspected to comprise a multiprotein complex localized to the cell membrane. I will collaborate with structural biologists led by Ivan Rayment (Department of Biochemistry, UW-Madison) to gain insights into the mechanism of function of CobC, and to advance our understanding of the implications of the existence of a membrane associated biosynthetic complex.

Public Health Relevance

Coenzyme B12 is only synthesized by prokaryotes, including many pathogens, and it is essential to the survival of animals, including humans. A better understanding of the biochemistry of coenzyme B12 biosynthesis will facilitate the design of antimicrobials that could be used to target disease-causing bacteria. In collaboration with others, our laboratory used knowledge gained from the studies of coenzyme B12 synthesis in our fight against cancer. A multifaceted approach will be applied to learn more about the last step of the pathway, which, in Salmonella enterica, it may occur outside the cell.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
1F31GM095230-01
Application #
8006486
Study Section
Special Emphasis Panel (ZRG1-IMST-D (29))
Program Officer
Gaillard, Shawn R
Project Start
2011-01-11
Project End
2014-01-10
Budget Start
2011-01-11
Budget End
2012-01-10
Support Year
1
Fiscal Year
2011
Total Cost
$41,800
Indirect Cost
Name
University of Wisconsin Madison
Department
Microbiology/Immun/Virology
Type
Schools of Earth Sciences/Natur
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Tavares, Norbert K; VanDrisse, Chelsey M; Escalante-Semerena, Jorge C (2018) Rhodobacterales use a unique L-threonine kinase for the assembly of the nucleotide loop of coenzyme B12. Mol Microbiol 110:239-261
Tavares, Norbert K; Zayas, Carmen L; Escalante-Semerena, Jorge C (2018) The Methanosarcina mazei MM2060 Gene Encodes a Bifunctional Kinase/Decarboxylase Enzyme Involved in Cobamide Biosynthesis. Biochemistry 57:4478-4495
Tavares, Norbert K; Escalante-Semerena, Jorge C (2017) A snapshot of evolution in action: emergence of new heme transport function derived from a coenzyme B12 biosynthetic enzyme. Environ Microbiol 19:8-10