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A study of membrane-bound cytochromes c participating in photosynthesis and respiration in Rhodobacter.
- Format:
- Book
- Thesis/Dissertation
- Author/Creator:
- Myllykallio, Hannu Juhani.
- Language:
- English
- Subjects (All):
- Plant physiology.
- Biochemistry.
- Microbiology.
- Molecular biology.
- 0307.
- 0410.
- 0487.
- 0817.
- Local Subjects:
- 0307.
- 0410.
- 0487.
- 0817.
- Physical Description:
- 177 pages
- Contained In:
- Dissertation Abstracts International 59-04B.
- System Details:
- Mode of access: World Wide Web.
- text file
- Summary:
- Rhodobacter capsulatus contains several c-type cytochromes. Two of them, the periplasmic cyt $c\sb2$ and the membrane bound cyt $c\sb{y},$ are capable of connecting the cyt $bc\sb1$ complex to the photochemical reaction center and the cyt c oxidase, and hence supporting photosynthetic and aerobic respiratory growth. The detailed functional and physico-chemical properties of cyt $c\sb2$ have been extensively characterized previously; however, much less was known about the corresponding properties of cyt $c\sb{y}$ prior to this work. Therefore, topology analyses and the purification of R. capsulatus cyt $c\sb{y}$ were undertaken. The results indicate that the amino-terminal signal sequence-like domain of cyt $c\sb{y}$ is sufficient to attach cyt $c\sb{y}$ to the membrane. Moreover, it was shown that the physico-chemical properties of cytochromes $c\sb2$ and $c\sb{y}$ closely resemble each other, suggesting that their different electron transfer properties are likely due to the differences in their cellular localization (i.e. periplasm vs. cytoplasmic membrane). Consequently, it was demonstrated that, presumably due to the relative immobility of cyt $c\sb{y}$ in the membrane, cyt $c\sb{y}$ is capable of supporting multiple turnovers of the photosynthetic electron transfer chain more efficiently than cyt c$\sb2.$ Unexpectedly, a c-type cytochrome homologous to R. capsularus cyt $c\sb{y}$ was discovered also in R. sphaeroides. This cytochrome was found to be unable to support photosynthetic growth, but yet it is fully functional in respiration. The function of this cyt c was further investigated by constructing chimera between R. capsulatus and R. sphaeroides cytochromes $c\sb{y}.$ These findings raise an intriguing issue with regard to the evolution of various electron carriers participating in respiratory electron transfer.
- Notes:
- Source: Dissertation Abstracts International, Volume: 59-04, Section: B, page: 1531.
- Adviser: Fevzi Daldal.
- Thesis (Ph.D.)--University of Pennsylvania, 1998.
- Local Notes:
- School code: 0175.
- ISBN:
- 9780591828184
- Access Restriction:
- Restricted for use by site license.
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