Of the A. marina chromosome nucleotide sequence (vs. itself) shows 18.7 of the sequence (not including the original, duplicated sequence) has a homology of greater than E 1 10 10 to another location on the chromosome. This is significantly higher than the 11.2 and 5.8 duplication in Synechocystis PCC6803 and Nostoc sp. PCC7120, respectively. A. marina actually has far fewer duplicated regions t
Of the A. marina chromosome nucleotide sequence (vs. itself) shows 18.7 of the sequence (not including the original, duplicated sequence) has a homology of greater than E 1 10 10 to another location on the chromosome. This is significantly higher than the 11.2 and 5.8 duplication in Synechocystis PCC6803 and Nostoc sp. PCC7120, respectively. A. marina actually has far fewer duplicated regions t
R plants also synthesize both - and -carotene; however, -carotene is used primarily as a precursor of lutein, and only -carotene is found in reaction centers. Future biochemical work may indicate whether a preferential interaction between Chl d and -carotene (rather than -carotene) could account for its exclusivity in the reaction center. The chromosome of A. marina codes for 11 proteins predicted
Possible that the means of Chl d synthesis could be completely unrelated to anything familiar in chlorophyll chemistry, it is far more likely that an enzyme has been recruited from related pathways. Major sources of interest are the large pool of proteins orthologous to ``Chl degradation'' and aromatic ring breakage,PNAS February 12, 2008 vol. 105 no. 6GENETICSFig. 2. Phylogenetic relationship of
Synthesis (Fig. 3). There is no clear differentiation that would explain the near-complete conversion of -carotene to zeaxanthin by -carotene hydroxylase (CrtR), the enzyme responsible for zeaxanthin biosynthesis. We suggest a putative carotene biosynthesis pathway (Fig. 3) that accommodates the distinct complement of the carotenoid biosynthesis enzymes and their end products in A. marina.Light-Ha
R plants also synthesize both - and -carotene; however, -carotene is used primarily as a precursor of lutein, and only -carotene is found in reaction centers. Future biochemical work may indicate whether a preferential interaction between Chl d and -carotene (rather than -carotene) could account for its exclusivity in the reaction center. The chromosome of A. marina codes for 11 proteins predicted
Ese genes are more closely related to those in filamentous cyanobacteria than the other -carotene-containing Prochlorococcus species.2008 www.pnas.org cgi doi 10.1073 pnas.A. marina is the only cyanobacterium found to contain both cruA and cruP, responsible for - and -carotene synthesis, in addition to lycopene cyclase (crtL) (35, 36). One class of cyclase, CrtL-e for -cyclase, was identified as t
Ese genes are more closely related to those in filamentous cyanobacteria than the other -carotene-containing Prochlorococcus species.2008 www.pnas.org cgi doi 10.1073 pnas.A. marina is the only cyanobacterium found to contain both cruA and cruP, responsible for - and -carotene synthesis, in addition to lycopene cyclase (crtL) (35, 36). One class of cyclase, CrtL-e for -cyclase, was identified as t