Analysis of a putative crtW gene of Myxococcus xanthus
Needham, James (2009) Analysis of a putative crtW gene of Myxococcus xanthus. PhD thesis, University of Warwick.
WRAP_THESIS_Needham_2009.pdf - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Official URL: http://webcat.warwick.ac.uk/record=b2334497~S15
Carotenoids are produced by all photosynthetic organisms and a large number
of bacteria and fungi. They are responsible for a lot of pigmentation in nature, as well
as often playing an essential role in the provision of light protection to cells and as
precursors of vitamin A in higher organisms. Myxobacton is the primary carotenoid
ester generated in the photoresistant bacterium Myxococcus xanthus. It is created
through a complex light-regulated gene expression cascade and acts to protect the
bacteria from blue light and the resultant generation of damaging singlet oxygen
species in the presence of porphyrins. The final stage in its production is a
ketonisation, and the enzyme responsible for this stage was unknown in M. xanthus.
We propose a possible location for the gene encoding such a ketolase, crtW. The
gene is found located within a four-gene operon separate from the other known
carotenoid biosynthetic genes, and appears to have two alternative promoter regions.
The additional genes in the operon were found to encode a putative MutT/Nudix
family hydrolase and a periplasmic, molybdopterin and haeme-dependent
oxidoreductase, YedYZ. It is also shown that crtW transcription is independent of
cell exposure to blue light and that the product is an inner membrane, integral
membrane protein probable ketolase. The evolutionary origins of crtW are considered
in conjunction with a number of other carotenoid biosynthetic enzymes, suggesting
that the gene was one of the last to be acquired by M. xanthus.
|Item Type:||Thesis or Dissertation (PhD)|
|Subjects:||Q Science > QR Microbiology|
|Library of Congress Subject Headings (LCSH):||Myxococcus xanthus -- Genetics, Carotenoids -- Research, Photosynthetic pigments -- Research|
|Official Date:||September 2009|
|Institution:||University of Warwick|
|Theses Department:||Department of Biological Sciences|
|Supervisor(s)/Advisor:||Hodgson, D. A. (David A.)|
|Format of File:|
|Extent:||220 leaves : ill., charts|
Actions (login required)