The general goal of these studies is to identify and characterize proteins and protein complexes that serve as morphogenetic factors in membrane assembly. In particular, we are interested in membrane-associated factors that control the differentiation of chloroplast membranes into appressed (grana) membrane regions, and non-appressed (stroma) membrane regions. Chloroplast membranes are an excellent model system for the investigation of membrane morphogenesis, both because of their characteristic architecture, which is controlled by genetic and environmental factors, and because they are the best studied membrane system from a biochemical, structural and genetic perspective. Proteins associated with the photosystem II-related light harvesting complexes (LHC II's) appear to play a major role in the formation of appressed membrane regions. These are encoded by two large, highly homologous gene families. We have developed an improved native gel system for membrane protein complexes which allows us to separate up to ten LHC II chlorophyll-protein complexes, there by providing the opportunity to correlate the appearance and accumulation of individual complexes with the formation of specific membrane configurations. We will prepare nonspecific antibodies against synthetic peptides corresponding to unique sequence domains of LHC II genes, and use these antibodies to study the composition of different LHC II complexes, the hierarchy of their appearance during development, and their degradation during adaptation to different light environments. We have also identified a set of ch1 b-deficient mutants with altered LHC II patterns exhibiting different structural phenotypes. We propose to associate these mutants with particular blocks in the chlorophyll biosynthesis pathway. A second line of work will focus on the composition and assembly of six different photosystem I-related complexes that we can also separate on our improved native gel system. Preliminary experiments show that this gel system has great potential for analyzing photosystem I-defective mutants in Chlamydomonas.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM022912-17
Application #
2174000
Study Section
Molecular Cytology Study Section (CTY)
Project Start
1976-05-01
Project End
1995-08-31
Budget Start
1993-09-01
Budget End
1995-08-31
Support Year
17
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Colorado at Boulder
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
City
Boulder
State
CO
Country
United States
Zip Code
80309
Falbel, T G; Meehl, J B; Staehelin, L A (1996) Severity of mutant phenotype in a series of chlorophyll-deficient wheat mutants depends on light intensity and the severity of the block in chlorophyll synthesis. Plant Physiol 112:821-32
Sigrist, M; Staehelin, L A (1994) Appearance of type 1, 2, and 3 light-harvesting complex II and light-harvesting complex I proteins during light-induced greening of barley (Hordeum vulgare) etioplasts. Plant Physiol 104:135-45
van der Staay, G W; Staehelin, L A (1994) Biochemical characterization of protein composition and protein phosphorylation patterns in stacked and unstacked thylakoid membranes of the prochlorophyte Prochlorothrix hollandica. J Biol Chem 269:24834-44
Meckenstock, R U; Krusche, K; Staehelin, L A et al. (1994) The six fold symmetry of the B880 light-harvesting complex and the structure of the photosynthetic membranes of Rhodopseudomonas marina. Biol Chem Hoppe Seyler 375:429-38
Falbel, T G; Staehelin, L A (1994) Characterization of a family of chlorophyll-deficient wheat (Triticum) and barley (Hordeum vulgare) mutants with defects in the magnesium-insertion step of chlorophyll biosynthesis. Plant Physiol 104:639-48
Sigrist, M; Staehelin, L A (1992) Identification of type 1 and type 2 light-harvesting chlorophyll a/b-binding proteins using monospecific antibodies. Biochim Biophys Acta 1098:191-200
Allen, K D; Staehelin, L A (1991) Resolution of 16 to 20 chlorophyll-protein complexes using a low ionic strength native green gel system. Anal Biochem 194:214-22
Allen, K D; Duysen, M E; Staehelin, L A (1988) Biogenesis of thylakoid membranes is controlled by light intensity in the conditional chlorophyll b-deficient CD3 mutant of wheat. J Cell Biol 107:907-19
Seibert, M; DeWit, M; Staehelin, L A (1987) Structural localization of the O2-evolving apparatus to multimeric (tetrameric) particles on the lumenal surface of freeze-etched photosynthetic membranes. J Cell Biol 105:2257-65
Craig, S; Moore, P J; Dunahay, T G (1987) Immunogold localization of intra- and extra-cellular proteins and polysaccharides of plant cells. Scanning Microsc 1:1431-7

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