The broad, long-term objective of the project is to understand the structure and function relationship of enzymes that catalyze reactions around cystathione, a central intermediate in the trans-sulfuration pathways that inter-convert cysteine and homocysteine. The trans-sulfuration enzymes play important roles in supplying cysteine and methionine for growth and in regulating the homeostasis of these amino acids. Certain genetic diseases in humans, such as homocysteinemia, are caused by mutations in the genes for these enzymes.
The specific aim of project is to characterize the enzymatic function and physiological role of a gene encoded by locus At1g33320 of the genetic model plant Arabidopsis thaliana. Based on sequence homology this gene was proposed to encode cystathionine gamma-synthase, a carbon-oxygen lyase. However, preliminary evidence suggests that it functions as cystathionine beta-lyase, a carbon-sulfur tyase. This hypothesis will be examined by carrying out in vitro enzyme kinetic experiments, and by examining the function of the enzyme under in vivo conditions using a genetic complementation test. The physiological role of the gene product will also be explored by studying its expression, its subcellular localization, and by examining the phenotype resulting from knock-out mutation of the gene. ? ?
| Hudson, Andre O; Gilvarg, Charles; Leustek, Thomas (2008) Biochemical and phylogenetic characterization of a novel diaminopimelate biosynthesis pathway in prokaryotes identifies a diverged form of LL-diaminopimelate aminotransferase. J Bacteriol 190:3256-63 |
| Hudson, Andre O; Singh, Bijay K; Leustek, Thomas et al. (2006) An LL-diaminopimelate aminotransferase defines a novel variant of the lysine biosynthesis pathway in plants. Plant Physiol 140:292-301 |
| McCoy, Andrea J; Adams, Nancy E; Hudson, Andre O et al. (2006) L,L-diaminopimelate aminotransferase, a trans-kingdom enzyme shared by Chlamydia and plants for synthesis of diaminopimelate/lysine. Proc Natl Acad Sci U S A 103:17909-14 |
| Hudson, Andre' O; Bless, Christine; Macedo, Polliana et al. (2005) Biosynthesis of lysine in plants: evidence for a variant of the known bacterial pathways. Biochim Biophys Acta 1721:27-36 |
