Professor of Biochemistry and Member, Molecular Biology Institute; BS and PhD, University of Wisconsin-Madison; Post-doctoral Scholar, Harvard University; Searle Scholar; National Institutes of Health Research Career Development Award; UCLA Faculty Career Development Awards;  Guggenheim Foundation Fellow; Charles Albert Shull Award of ASPB.


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.


From my Ph.D. thesis research

From my Post-Doctoral Research

From my Group 1990-1995

From my Group 1996-2000

From my Group 2001-Present

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.

From my sabbatical in the Schatz group at the Biozentrum in Basel

49. Koehler, C. M., Merchant, S., Oppliger, W., Schmid, K., Jarosch, E., Dolfini, L., Junne, T., Schatz, G., Tokatlidis, K. (1998) Tim9p, An Essential Partner Subunit of Tim10p for the Import of Mitochondrial Carrier Proteins. EMBO J. 17:6477-6486.

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

From my sabbatical in the Schekman group at UC-Berkeley

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.


1. Rochaix, J.-D., Goldschmidt-Clermont, M., Merchant, S., eds. (1998) Molecular Biology of Chlamydomonas: Chloroplasts and Mitochondria. Advances in Photosynthesis (Govindjee, series ed.), Kluwer Academic Publishers.


Department of Chemistry and Biochemistry
Box 951569 (post)
607 Charles E. Young Drive East (courier)
Los Angeles, CA  90095-1569



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GROUP MEMBERS - Merchant Group Resources

  • 1991
  • 1993
  • 1994
  • 1998
  • 2000
  • 2001
  • 2002
  • Former Ph.D. Students
    Gregg Howe - Gregg's rememberances of UCLA - Pictures of Greg's Baby, "EJ"!
    Kent Hill
    Hong Hua Li - - Baby Pictures of Kevin & Kelly!
    Jeffrey Moseley -
    Stacie Nakamoto -
    Zhiyi Xie -

    Former Post-doctoral Scholars
    Ute Boronowsky -
    Duane Culler
    Beth Dreyfuss -
    Mats Eriksson -
    Sharon La Fontaine - - Visit with Sharon
    M. Dudley Page -
    Tomas Westergren -
    Jeanette Quinn -

    Former Visitors
    Paola Barraco -- Paola and Luca got married

    Ph.D. Students presently in the group
    Michael Allen - - Michael's Project
    Delphine Bernard -

    Post-doctoral Scholars presently in the group
    Jose del Campo -
    Maria Felix Vazquez-Bermudez -
    Patrice Hamel - - Patrice wins Boyer Award - March 2003
    Janette Kropat -
    Stephen Tottey -

    Elida Escalante -
    Stephane Gabilly -


    Rotation Students


    Deb Berthold - - on structural analysis of Crd1
    Maryse Block - - on localization of chlorophyll biosynthesis enzymes
    David Bollivar-
    Jean-Pierre Carde - on localization of chlorophyll biosynthesis enzymes
    Ken Cline - - on localization of chlorophyll biosynthetic enzymes
    Genevieve Dujardin - - on mitochondrial cytochrome biogenesis
    Michael Hippler - - on molecular responses to Fe-deficiency
    Poul Erik Jensen - - on the aerobic oxidative cyclase in chlorophyll biosynthesis
    Saul Purton - - on b cytochrome biogenesis
    Krishna Niyogi - - on Chlamydomonas microarrays
    Steve Theg- - on localization of plastid proteins
    Chris Vulpe - - on Chloamydomonas microarrays
    Francis-Andre Wollman - - on b and c type cytochrome mutants

    Dan Kosman - on copper uptake
    Laurie Mets - - on genetic analysis of plastocyanin and cytochrome mutants
    Todd Yeates - - on structural analysis of plastocyanin and cytochrome c6

    Brisbane, Australia 2001
    Lake Tahoe 2002

    Joshua Tree 2003

    Embo Workshop 2003
    Gordon Research Conference 2003

    Ischia 2003
    2003 UCLA Plant Biology


    Research Resources




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