Understanding the integration of metabolic pathways will be one of the challenges for biologists in the post-genomics era. To meet this challenge, cell physiologists will rely on solid knowledge of the biochemistry underpinning the metabolic pathways in the cell. The study of major metabolic pathways like the one dedicated to the synthesis of adenosylcobalamin (coenzyme B12) offers an opportunity to reveal the strategies used by the cell to manufacture the most structurally complex coenzyme whose steady intracellular level is very low, and to learn how this major pathway is integrated with other metabolic processes in the cell. De novo synthesis of coenzyme B12 is performed only by procaryotes, but it is an essential nutrient for humans and animals in general. A diet devoid of cobalamin leads to a condition known as pernicious anemia. The inability of the human cell to convert the vitamin form to its coenzymic form results in severe health problems. Conversion of the vitamin to the coenzymic form requires the attachment of the upper ligand 5'-deoxyadenosine, and this reaction is catalyzed by an adenosyltransferase enzyme. One of the objectives of the proposed work is to further our understanding of how a bacterial adenosyltransferase enzyme works. This knowledge will serve as the foundation for future work on the human enzyme aimed at solving the problem of the lack or lower activity of this enzyme. We are also studying the enzyme that catalyzes a reaction critical to the use of precursors present in the environment and to de novo coenzyme B12 biosynthesis. A complete understanding of how this enzyme works will facilitate the design of drugs that could block its activity, thus preventing salvaging and de novo synthesis of coenzyme B12. Gaps of knowledge remain regarding many aspects of the coenzyme B12 biosynthetic pathway. We take a multifaceted approach to fill these gaps, and work together with structural biologists and chemists to bring our understanding of these processes to a level not afforded by single-discipline . approaches.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM040313-16
Application #
6830696
Study Section
Special Emphasis Panel (ZRG1-VR (01))
Program Officer
Preusch, Peter C
Project Start
1988-09-01
Project End
2006-06-30
Budget Start
2004-12-01
Budget End
2006-06-30
Support Year
16
Fiscal Year
2005
Total Cost
$281,027
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
Mattes, Theodoric A; Escalante-Semerena, Jorge C (2018) Facile isolation of ?-ribazole from vitamin B12 hydrolysates using boronate affinity chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 1090:52-55
Park, Kiyoung; Mera, Paola E; Moore, Theodore C et al. (2015) Unprecedented Mechanism Employed by the Salmonella enterica EutT ATP:Co(I)rrinoid Adenosyltransferase Precludes Adenosylation of Incomplete Co(II)rrinoids. Angew Chem Int Ed Engl 54:7158-61
Newmister, Sean A; Otte, Michele M; Escalante-Semerena, Jorge C et al. (2011) Structure and mutational analysis of the archaeal GTP:AdoCbi-P guanylyltransferase (CobY) from Methanocaldococcus jannaschii: insights into GTP binding and dimerization. Biochemistry 50:5301-13
Mera, Paola E; Escalante-Semerena, Jorge C (2010) Dihydroflavin-driven adenosylation of 4-coordinate Co(II) corrinoids: are cobalamin reductases enzymes or electron transfer proteins? J Biol Chem 285:2911-7
Gray, Michael J; Escalante-Semerena, Jorge C (2010) A new pathway for the synthesis of ?-ribazole-phosphate in Listeria innocua. Mol Microbiol 77:1429-38
Claas, Kathy R; Parrish, J R; Maggio-Hall, L A et al. (2010) Functional analysis of the nicotinate mononucleotide:5,6-dimethylbenzimidazole phosphoribosyltransferase (CobT) enzyme, involved in the late steps of coenzyme B12 biosynthesis in Salmonella enterica. J Bacteriol 192:145-54
Otte, Michele M; Escalante-Semerena, Jorge C (2009) Biochemical characterization of the GTP:adenosylcobinamide-phosphate guanylyltransferase (CobY) enzyme of the hyperthermophilic archaeon Methanocaldococcus jannaschii. Biochemistry 48:5882-9
Gray, Michael J; Escalante-Semerena, Jorge C (2009) The cobinamide amidohydrolase (cobyric acid-forming) CbiZ enzyme: a critical activity of the cobamide remodelling system of Rhodobacter sphaeroides. Mol Microbiol 74:1198-210
Gray, Michael J; Escalante-Semerena, Jorge C (2009) In vivo analysis of cobinamide salvaging in Rhodobacter sphaeroides strain 2.4.1. J Bacteriol 191:3842-51
Mera, Paola E; St Maurice, Martin; Rayment, Ivan et al. (2009) Residue Phe112 of the human-type corrinoid adenosyltransferase (PduO) enzyme of Lactobacillus reuteri is critical to the formation of the four-coordinate Co(II) corrinoid substrate and to the activity of the enzyme. Biochemistry 48:3138-45

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