Elisabeth Gantt

Ph.D. - Northwestern University, 1963

Distiguished University Professor

Department of Cell Biology and Molecular Genetics

University of Maryland

College Park, MD 20742

Telephone: (301)-405-1625

Fax: (301)-405-1625

E-mail: egantt@umd.edu

Research Interests: Plant Cell and Molecular Biology, Isoprenoid Synthesis.

     The major interest in our laboratory is the biosynthesis of carotenoids and the regulation of other isoprenoids related to photosynthesis.
     In cyanobacteria and plants, isoprenoid biosynthesis is required for production of many essential compounds. Among these are vitamins, carotenoids for photoprotection of photosynthesis, quinones for electron transport, and in plants, compounds for flower and fruit coloration and production of scents. The 5-carbon precursors for isoprenoid synthesis, isopentenyl diphosphate and dimethylallyl diphosphate, can be formed by two pathways. The well-studied MVA (mevalonic acid) pathway is found in certain bacteria, fungi, animals and the cytoplasm of plants. The recently recognized MEP (2-C-methyl-D-erythritol 4-phosphate) pathway is present in plant plastids, cyanobacteria and in other bacteria, as typified by Escherichia coli. Cyanobacteria, possessing the MEP pathway, are of interest as probable ancestors of chloroplasts. Isoprenoid synthesis in the cyanobacterium Synechocystis PCC6803 is being investigated to determine if the MEP pathway is the primary pathway by which isoprenoids are synthesized. Although this cyanobacterium and E. coli share genes of the MEP pathway, our evidence has revealed significant differences in the functioning of the pathway in these two. Objectives being addressed will determine: (1) if IPP and DMAPP are synthesized by separate branches in cyanobacteria, without a major dependence on interconversion by an IPP isomerase; (2) if substrates enter the MEP pathway before or after MEP; and (3) whether the same substrates are utilized under photosynthetic and non-photosynthetic conditions.

     Sun, Z., F.X. Cunningham, and E. Gantt. 1998. Differential expression of two isopentenyl pyrophosphate isomerases and enhanced carotenoid accumulation in a unicellular chlorophyte. Proc. Natl. Acad. Sci. (USA) 95: 11482-11488.
     Durnford, D.G., J.A. Deane, S. Tan, G.I. McFadden, E. Gantt, and B.R. Green. 1999. Phylogenetic assessment of the eukaryotic light-harvesting antenna proteins, with implications for plastid evolution. J. Mol. Evol. 48: 59-68.
     Grabowski, B., S. Tan, F.X. Cunningham, and E. Gantt. 2000. Characterization of the Porphyridium cruentum Chl a-binding LHC by in vitro reconstitution: LHCaR1 binds 8 Chl a molecules and proportionately more carotenoids than CAB proteins. Photosyn. Res. 63: 85-96.
     Cunningham, F.X., and E. Gantt. 2000. Identification of multi-gene families encoding isopentenyl diphosphate isomerase in plants by heterologous complementation in Escherichia coli. Plant and Cell Physiol. 41: 119-123.
     Ershov, Y., R.R. Gantt, F.X. Cunningham, and E. Gantt. 2000. Isopentenyl diphosphate isomerase deficiency in Synechocystis sp. strain PCC6803. FEBS Letters. 473: 337-340.
     Cunningham, F.X., T. Lafond, and E. Gantt. 2000. A possible role for LYTB in the non-mevalonate pathway of isoprenoid biosynthesis. J. Bacteriol. 182: 5841-5848.
     Grabowski, B., F.X. Cunningham, Jr., and E. Gantt. 2001. Chlorophyll and carotenoid binding in a simple red algal complex crosses phylogenetic lines. Proc. Natl. Acad. Sci. (USA). 98: 2911-2916.
     Cunningham, F.X., Jr. and E. Gantt. 2001. One ring or two? Determination of ring number in carotenoids by lycopene e-cyclase. Proc. Natl. Acad. Sci. (USA). 98: 2905-2910.
     Cunningham, F.X., Jr. and E. Gantt. 2002. Molecular control of floral pigmentation: Carotenoids. pp. 273-293. In: A. Vainstein (ed.) Breeding for Ornamentals-classical and Molecular Approaches. Kluwer Academic Publishers, The Netherlands.
     Ershov, Y., R.R. Gantt, F.X. Cunningham, Jr. and E. Gantt. 2002. Isoprenoid biosynthesis in Synechocystis PCC6803 is stimulated by compounds of the pentose phosphate cycle but not by pyruvate and deoxyxylulose-5-phosphate. J. Bact. (In press).