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
Ith a lambda-phage cI motif are also likely correlated with the extra recA (22, 24). The presence of multiples copies of recA and related enzymes could account for gene duplication and/or integration of foreign genes that would lead to genome expansion. Based on the comparative analysis of many genomes, Konstantinidis et al. (21) hypothesized that species with large genomes may dominate noncompeti
Tosynthetic pigments appears to have incurred only minimal specializations in reaction center proteins to accommodate these alternate pigments. These features clearly show that the genus Acaryochloris is a fitting candidate for understanding genome expansion, gene acquisition, ecological adaptation, and photosystem modification in the cyanobacteria.comparative microbial genomics photosynthesis oxy
Ed in Na -transport. However, it is clear that this class of ATP synthase does not share any greater degree of similarity to Na -transport systems in Ilyobacter tartaricus and others (27) than to other ATP synthases. The primary sequences of these proteins are so divergent from other ATP synthases that a thorough biochemical study is needed to confidently propose a functional role.Chlorophyll Bios
Ed in Na -transport. However, it is clear that this class of ATP synthase does not share any greater degree of similarity to Na -transport systems in Ilyobacter tartaricus and others (27) than to other ATP synthases. The primary sequences of these proteins are so divergent from other ATP synthases that a thorough biochemical study is needed to confidently propose a functional role.Chlorophyll Bios
Ed in Na -transport. However, it is clear that this class of ATP synthase does not share any greater degree of similarity to Na -transport systems in Ilyobacter tartaricus and others (27) than to other ATP synthases. The primary sequences of these proteins are so divergent from other ATP synthases that a thorough biochemical study is needed to confidently propose a functional role.Chlorophyll Bios