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
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
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
Ecies (32). Such enzymes could provide another means for Chl d biosynthesis. A. marina codes for 12 proteins with putative radical SAM motifs, far more than expected from an oxygen-producing cyanobacterium. Of these 12, two (AM1 5023 and AM1 5798) share very little homology with other sequenced cyanobacteria. The Chl d biosynthesis pathway may not be as simple as expected. Unlike the formyl side c
Cyanobacteria and higher plantscontain -carotene as a primary carotenoid found in both PSI and PSII (Fig. 3). In the case of A. marina, -carotene was detected instead of -carotene, and zeaxanthin, an oxidative product of -carotene, was identified as a major carotenoid (4, 13). A similar carotenoid composition has been reported only in Prochlorococcus species that contain atypical, divinyl-Chls, an
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