Analyses of mutants in the 33 kDa manganese stabilizing protein of photosystem II and construction of a deletion mutant in synechococcus PCC 7942

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dc.contributor.advisor Vann, Carolyn N. en_US Lee, Sengyong en_US 2011-06-03T19:36:28Z 2011-06-03T19:36:28Z 1993 en_US 1993
dc.identifier LD2489.Z78 1993 .L44 en_US
dc.description.abstract The 33 kDa manganese stabilizing protein (MSP) has been proposed to provide ligands to stabilize Mn ions in the water lysis reaction of photosystem II of photosynthesis. In previous research site-directed mutagenesis had been performed on regions of the psbO gene encoding two aspartic acid residues of MSP which were thought to have the potential to form carboxyl bridges with Mn ions. The purpose of this research was to analyze these mutants. Plasmids pUC120-33 (#1,3,5,7,9,11,15) containing mutant psbO genes could not be isolated from E.coli because the expressed MSP was toxic to the cells. However, a psbO mutant gene carried in pPGV5-33 (#7) was isolated from E.coli and transformed into cyanobacterium Svnechococcus PCC 7942. Cyanobacterial cells carrying the MSP mutant showed a susceptibility to intensive light (100 footcandles) with a decrease of 30% in the growth rate within the first 100 hours after inoculation. This result suggested a possible function of the MSP in protecting the oxygen evolving complex from intensive light exposure. However, the mutant appeared to revert after this time probably due to homologous gene recombination with the wild type gene. In order to further analyze the function of mutants without recombination occurring, the construction of an MSP deletion was attempted using insertion of a kanamycin cartridge into the middle of the psbO gene. The inactivated psbO gene was transformed into E.coli and transformants were selected by kanamycin resistance. However, plasmid DNA carrying the interrupted genes could not be isolated, probably due to toxicity of the expression product in E.coli cells. Thus, future studies should be directed to reconstruction of a deletion mutant by direct transformation into cyanobacterial cells. Once a deletion mutant has been constructed analyses of the site-directed mutations could be performed in cyanobacteria.
dc.description.sponsorship Department of Biology
dc.format.extent vi, 58 leaves : ill. ; 28 cm. en_US
dc.source Virtual Press en_US
dc.subject.lcsh Photosynthesis. en_US
dc.subject.lcsh Photosynthetic bacteria -- Ultrastructure. en_US
dc.subject.lcsh Cyanobacteria -- Physiology. en_US
dc.subject.lcsh Photosynthesis -- Genetic aspects. en_US
dc.subject.lcsh Metalloproteins. en_US
dc.title Analyses of mutants in the 33 kDa manganese stabilizing protein of photosystem II and construction of a deletion mutant in synechococcus PCC 7942 en_US Thesis (M.S.)
dc.identifier.cardcat-url en_US

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  • Master's Theses [5318]
    Master's theses submitted to the Graduate School by Ball State University master's degree candidates in partial fulfillment of degree requirements.

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