Using a combination of organic chemistry, molecular biology, enzymology, and NMR spectroscopy the details of the biosynthesis of uroporphyrinogen III (the precursor of heme and chlorophyll) and its subsequent transformation to Vitamin B12, the anti-pernicious anemia factor, will be elucidated. Knowledge of the pathway including control mechanisms and genetic mapping will define intermediates important in diseases such as B12 deficiency and porphyria. The mechanisms of several B12 dependent mutases will be studied using NMR spectroscopy of enzymatically enriched substrates. In particular, methyl malonyl CoA mutase, a mammalian enzyme whose deficiency causes metabolic disorder, will be examined in detail and its mode of action determined by a combination of NMR spectroscopy and cryoenzymology. The latter technique is also the method to be used in studying the many enzymes of the pathway from aminolevulinic acid (ALA) to B12.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Research Project (R01)
Project #
Application #
Study Section
Metallobiochemistry Study Section (BMT)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Texas Agrilife Research
Schools of Earth Sciences/Natur
College Station
United States
Zip Code
Ji, Qi; Williams, Howard J; Roessner, Charles A et al. (2007) Biomimetic self-condensation of malonates mediated by nucleosides. Tetrahedron Lett 48:8026-8028
Williams, Lakenya; Fresquet, Vicente; Santander, Patricio J et al. (2007) The multiple amidation reactions catalyzed by Cobyric acid synthetase from Salmonella typhimurium are sequential and dissociative. J Am Chem Soc 129:294-5
Kajiwara, Yasuhiro; Santander, Patricio J; Roessner, Charles A et al. (2006) Genetically engineered synthesis and structural characterization of cobalt-precorrin 5A and -5B, two new intermediates on the anaerobic pathway to vitamin B12: definition of the roles of the CbiF and CbiG enzymes. J Am Chem Soc 128:9971-8
Santander, Patricio J; Kajiwara, Yasuhiro; Williams, Howard J et al. (2006) Structural characterization of novel cobalt corrinoids synthesized by enzymes of the vitamin B12 anaerobic pathway. Bioorg Med Chem 14:724-31
Roessner, Charles A; Scott, A Ian (2006) Fine-tuning our knowledge of the anaerobic route to cobalamin (vitamin B12). J Bacteriol 188:7331-4
Chow, Siew Yin; Williams, Howard J; Huang, Qiulong et al. (2005) Studies on taxadiene synthase: interception of the cyclization cascade at the isocembrene stage with GGPP analogues. J Org Chem 70:9997-10003
Roessner, Charles A; Williams, Howard J; Scott, A Ian (2005) Genetically engineered production of 1-desmethylcobyrinic acid, 1-desmethylcobyrinic acid a,c-diamide, and cobyrinic acid a,c-diamide in Escherichia coli implies a role for CbiD in C-1 methylation in the anaerobic pathway to cobalamin. J Biol Chem 280:16748-53
Raux, Evelyne; Leech, Helen K; Beck, Richard et al. (2003) Identification and functional analysis of enzymes required for precorrin-2 dehydrogenation and metal ion insertion in the biosynthesis of sirohaem and cobalamin in Bacillus megaterium. Biochem J 370:505-16
Roessner, Charles A; Huang, Ke-Xue; Warren, Martin J et al. (2002) Isolation and characterization of 14 additional genes specifying the anaerobic biosynthesis of cobalamin (vitamin B12) in Propionibacterium freudenreichii (P. shermanii). Microbiology 148:1845-53
Roessner, Charles A; Ponnamperuma, Krishan; Scott, A I (2002) Mutagenesis identifies a conserved tyrosine residue important for the activity of uroporphyrinogen III synthase from Anacystis nidulans. FEBS Lett 525:25-8

Showing the most recent 10 out of 16 publications