Thomas Leustek Professor Rutgers University Dept. of Plant Science Biotechnology Center for Agriculture & the Environment Rutgers University School of Env & Biol Sciences New Brunswick. NJ 08903 (732) 932-8165. Ext. 326 FAX - 0312 leustek@aesop.rutgers.edu

Biochemistry. Physiology

My research focuses on sulfur metabolism in higher plants. Plants and microorganisms are able to assimilate inorganic sulfate into organic forms. primarily cysteine and methionine. Animals are unable to assimilate sulfate. and so are dependent on ingesting plants and microorganisms for this nutrient. Both cysteine and methionine participate in a multitude of universally essential cellular functions. To name a few; (1) the thiol group of cysteine is required for protein structure and function. (2) methionine is required for initiation of translation. (3) glutathione functions as the primary modulator of cellular redox potential. (4) thiol groups of the protein metallothionein or the peptides known as phytochelatins are the primary defense against the toxic affects of heavy metals. Despite their importance. the pathways for cysteine and methionine biosynthesis or their regulation in plants are not fully understood. My laboratory is using a molecular genetic approach to explore this topic. We have used microorganisms for which mutants are known. to clone by functional complementation. the genes encoding enzymes in the cysteine and methionine biosynthetic pathways from higher plants. The cloning of these genes demonstrates. first. that they exist in higher plants and provides the tools with which to explore such questions as: (1) what are the kinetic and physical properties of the enzymes. (2) how are the enzymes and the pathway regulated. (3) does modification of the pathway affect the ability of an organism to tolerate heavy metals or oxidative stress?

Selected Publications

Chung JS, Noguera-Mazon V, Lancelin JM, Kim SK, Hirasawa M, Hologne M, Leustek T, Knaff DB. (2009) Interaction domain on thioredoxin for Pseudomonas aeruginosa 5'-adenylylsulfate reductase. J Biol Chem. 284(45):31181-9.

Hudson AO, Gilvarg C, Leustek T. (2008) Biochemical and phylogenetic characterization of a novel diaminopimelate biosynthesis pathway in prokaryotes identifies a diverged form of LL-diaminopimelate aminotransferase. J Bacteriol. 190(9):3256-63.

Martin MN, Saladores PH, Lambert E, Hudson AO, Leustek T. (2007) Localization of members of the gamma-glutamyl transpeptidase family identifies sites of glutathione and glutathione S-conjugate hydrolysis. Plant Physiol. 144(4):1715-32.

Muralla R, Sweeney C, Stepansky A, Leustek T, Meinke D. (2007) Genetic dissection of histidine biosynthesis in Arabidopsis. Plant Physiol. 144(2):890-903.

Kim SK, Gomes V, Gao Y, Chandramouli K, Johnson MK, Knaff DB, Leustek T. (2007) The two-domain structure of 5'-adenylylsulfate (APS) reductase from Enteromorpha intestinalis is a requirement for efficient APS reductase activity. Biochemistry. 46(2):591-601.

McCoy AJ, Adams NE, Hudson AO, Gilvarg C, Leustek T, Maurelli AT. (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(47):17909-14.

Stepansky A, Leustek T. (2006) Histidine biosynthesis in plants. Amino Acids. 30(2):127-42. Review.

Kim SK. Rahman A. Conover RC. Johnson MK. Mason JT. Gomes V. Hirasawa M. Moore ML. Leustek T. Knaff DB. (2006) Properties of the cysteine residues and the iron-sulfur cluster of the assimilatory 5'-adenylyl sulfate reductase from Enteromorpha intestinalis. Biochemistry. 45(15):5010-8.

Hudson AO. Singh BK. Leustek T. Gilvarg C. (2006) An LL-diaminopimelate aminotransferase defines a novel variant of the lysine biosynthesis pathway in plants. Plant Physiol. 140(1):292-301.

Martin MN. Tarczynski MC. Shen B. Leustek T. (2005) The role of 5'-adenylylsulfate reductase in controlling sulfate reduction in plants. Photosynth Res. 86(3):309-23.

Hell R. Leustek T. (2005) Sulfur metabolism in plants and algae--a case study for an integrative scientific approach. Photosynth Res. 86(3):297-8.

Kim SK. Rahman A. Mason JT. Hirasawa M. Conover RC. Johnson MK. Miginiac-Maslow M. Keryer E. Knaff DB. Leustek T. (2005) The interaction of 5'-adenylylsulfate reductase from Pseudomonas aeruginosa with its substrates. Biochim Biophys Acta. 1710(2-3):103-12.

Sors TG. Ellis DR. Na GN. Lahner B. Lee S. Leustek T. Pickering IJ. Salt DE. (2005) Analysis of sulfur and selenium assimilation in Astragalus plants with varying capacities to accumulate selenium. Plant J. 42(6):785-97.

Lee M. Martin MN. Hudson AO. Lee J. Muhitch MJ. Leustek T. (2005) Methionine and threonine synthesis are limited by homoserine availability and not the activity of homoserine kinase in Arabidopsis thaliana. Plant J. 41(5):685-96.

Hudson AO. Bless C. Macedo P. Chatterjee SP. Singh BK. Gilvarg C. Leustek T. (2005) Biosynthesis of lysine in plants: evidence for a variant of the known bacterial pathways. Biochim Biophys Acta. 1721(1-3):27-36.

Kim SK. Rahman A. Bick JA. Conover RC. Johnson MK. Mason JT. Hirasawa M. Leustek T. Knaff DB. (2004) Properties of the cysteine residues and iron-sulfur cluster of the assimilatory 5'-adenylyl sulfate reductase from Pseudomonas aeruginosa. Biochemistry. 43(42):13478-86.