Biochemistry and Molecular Genetics of Metal Metabolism
My research program encompasses four related projects: one dealing with the mechanism of signal transduction in the context of copper homeostasis, another dealing with iron metabolism, a third dealing with the mechanism of assembly of membrane-associated heme proteins, and a new project concerned with the cell biology of a key enzyme in chlorophyll biosynthesis, the aerobic cyclase.
A large fraction of proteins require metals (e.g. Zn, Cu, Fe, Mn) or metal-cofactors (hemes, FeS centers, chlorophylls, cobalamin, molybdopterin) for function. The metal is invariably an important structural constituent of the protein, and it is essential for function in the proteins where it serves a catalytic role. Metals and metal cofactors are found in every cellular compartment and they function in diverse metabolic pathways. In one genome (of a photosynthetic microorganism), cofactor/prosthetic group metabolism accounts for as much as 12% of its function. The chemical reactivity, exploited in biology to make desirable catalysts, can cause intracellular damage if it is not controlled. Metal metabolism is, therefore, subject to tight homeostatic regulation.
My group is addressing basic questions related to metal and metal cofactor metabolism. How is the abundance / availability of a cofactor within the cell controlled? How is the cofactor distributed to various organelles? Is there a hierarchy of distribution when the cofactor might be limiting (as a result of genetic lesion or sub-optimal nutritional supply)? What are the mechanisms that ensure highly selective association between a polypeptide and its cofactor?
Our attention is focused on both inorganic (copper, iron) redox-active cofactors and tetrapyrrole cofactors (heme, chlorophyll) that are found in quantity in electron transfer pathways, such as respiration and photosynthesis. My program is based on our discoveries relating to the biogenesis of photosynthetic catalysts in chloroplasts.
For more information on our projects, chose copper , heme, iron, or chlorophyll.
Positions for Ph.D. students and post-doctoral scholars are available on all projects. Candidates with demonstrated research productivity (publication record) and expertise in genetics or biochemistry are especially encouraged to apply for post-doctoral positions. Ph.D. candidates should apply to the Department of Chemistry and Biochemistry,to ACCESS, or to the Molecular Toxicology Inter-departmental program. I participate also in the Plant Biology program.
59. Quinn, J.M., Eriksson, M., Moseley, J.L., Merchant, S. (2002) Oxygen Deficiency Responsive Gene Expression in Chlamydomonas reinhardtii through a Copper-Sensing Signal Transduction Pathway Plant Physiol. 128:463-471.
60. LaFontaine, S., Quinn, J.M., Merchant, S. (2002) Comparative analysis of copper and iron metabolism in photosynthetic eukaryotes versus yeasts and mammals, in Handbook of Copper Pharmacology and Toxicology, Humana Press, Inc., ed. E.J. Massaro: Totowa, N.J. 481-502.
61. Moseley, J.L., Page, M.D., Alder, N.P., Eriksson, M., Quinn, J., Soto, F., Theg, M., Hippler, M., Merchant, S. (2002) Reciprocal expression of two candidate di-iron enzymes affecting photosystem I and light-harvesting complex accumulation. Plant Cell 14:673-688.
62. LaFontaine, S., Quinn, J.M., Nakamoto, S.S., Page, M.D., Göhre, V., Moseley, J.L., Kropat, J., Merchant, S. (2002) Copper-Dependent Iron Assimilation Pathway in the Model Photosynthetic Eukaryote Chlamydomonas reinhardtii. Eukaryotic Cell 1(5):736-757.
63. Moseley, J., Allinger, T., Herzog, P., Wehinger, E., Merchant, S., Hippler, M. (2002) Adaptation to Fe-deficiency requires re-modelling of the photosynthetic apparatus. EMBO J. 21: 6709-6720.
64. Dreyfuss, B.W., Hamel, P., Nakamoto, S.S., Merchant, S. (2003) Functional analysis of a divergent system II protein, Ccs1, involved in c-type cytochrome biogenesis. J. Biol. Chem. 278: 2604-2613.
65. Hamel, P., Dreyfuss, B.W., Xie, Z., Gabilly, S., Merchant, S. (2003) Essential histidine and tryptophan residues in CcsA, a system II polytopic cytochrome c biogenesis protein. J. Biol. Chem. 278: 2593-2603.
50. Koehler, C.M., Leuenberger, D., Merchant, S., Renold, A., Junne, T., Schatz, G. (1999) Human Deafness Dystonia Syndrome is a Mitochondrial Disease. Proc. Natl. Acad. Sci USA 96:2141-2146. see commentary
56. Springer, S., Chen, E., Duden, R., Marzioch, M., Rowley, A., Hamamoto, S., Merchant, S., Schekman, R. (2000) The p24 proteins are not essential for vesicular transport in Saccharomyces cerevisiae. Proc. Natl. Acad. Sci. USA 97:4034-4039. see commentary.
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GROUP MEMBERS - Merchant Group Resources
Former Ph.D. Students
Former Post-doctoral Scholars
Ute Boronowsky - firstname.lastname@example.org
Beth Dreyfuss - email@example.com
Mats Eriksson - firstname.lastname@example.org
Sharon La Fontaine - email@example.com - Visit with Sharon
M. Dudley Page - firstname.lastname@example.org
Tomas Westergren - email@example.com
Jeanette Quinn - firstname.lastname@example.org
Paola Barraco -- Paola and Luca got married
Ph.D. Students presently in the group
Michael Allen - email@example.com - Michael's Project
Delphine Bernard - firstname.lastname@example.org
Post-doctoral Scholars presently in the group
Jose del Campo - email@example.com
Maria Felix Vazquez-Bermudez - firstname.lastname@example.org
Patrice Hamel - email@example.com - Patrice wins Boyer Award - March 2003
Janette Kropat - firstname.lastname@example.org
Stephen Tottey - email@example.com
Elida Escalante - firstname.lastname@example.org
Stephane Gabilly - email@example.com
MERCHANT LAB COLLABORATORS
Deb Berthold - firstname.lastname@example.org - on structural analysis of Crd1
Maryse Block - email@example.com - on localization of chlorophyll biosynthesis enzymes
David Bollivar- firstname.lastname@example.org
Jean-Pierre Carde -email@example.com - on localization of chlorophyll biosynthesis enzymes
Ken Cline - firstname.lastname@example.org - on localization of chlorophyll biosynthetic enzymes
Genevieve Dujardin - email@example.com - on mitochondrial cytochrome biogenesis
Michael Hippler - firstname.lastname@example.org - on molecular responses to Fe-deficiency
Poul Erik Jensen - email@example.com - on the aerobic oxidative cyclase in chlorophyll biosynthesis
Saul Purton - firstname.lastname@example.org - on b cytochrome biogenesis
Krishna Niyogi - email@example.com - on Chlamydomonas microarrays
Steve Theg- firstname.lastname@example.org - on localization of plastid proteins
Chris Vulpe - email@example.com - on Chloamydomonas microarrays
Francis-Andre Wollman - firstname.lastname@example.org - on b and c type cytochrome mutants
Dan Kosman - on copper uptake
Laurie Mets - email@example.com - on genetic analysis of plastocyanin and cytochrome mutants
Todd Yeates - firstname.lastname@example.org - on structural analysis of plastocyanin and cytochrome c6
|PHOTOS AT MEETINGS||OTHER PHOTOS|
Lake Tahoe 2002
Joshua Tree 2003
Embo Workshop 2003
Gordon Research Conference 2003
|2003 UCLA Plant Biology|