Figures
- Carotenoid Biosynthesis in Cyanobacteria: Structural and Evolutionary Scenarios Based on Comparative Genomics

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Fig 1

Putative biosynthetic pathway of carotenoids in cyanobacteria. The names of enzymes are according to the crtE, geranylgeranyl pyrophosphate synthase; crtB, phytoene synthase; crtP, phytoene desaturase; crtQ, zeta-carotene desaturase; crtL, lycopene beta cyclase, ; lycopene epsilon cyclase; cruA, the most like candidate for lycopene cyclase by comparison to CT0456 in the species lacking crtL. crtO/crtW, beta-carotene ketolase; crtR, beta-carotene hydroxylase.

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Fig 2

Presumed enzymes involved in the biosynthetic pathway of carotenoids among different cyanobacterial species. Some enzymes have been functionally identified, while others are just suggested by sequence homology. Database searches were carried out with the BLASTP program. (a) Putative carotenoid synthetic pathway diagram. The shading reflects correspondence to specific genes, numbers and colors are the same as in (b). (b) A list of major enzymes and proteins involved in cyanobacterial carotenoid biosynthesis. Presence or absence of putative orthologs in a given genome is indicated by '+' or '-', respectively. The gene IDs of putative othologous genes are listed in supplemental material.

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Fig 3

Phylogenetic tree analysis of lycopene cylase based on the amino acid sequences of cyanobacteria, algae and plants by the neighbor-joining method. The Chloroflexus aurantiacus sequence, a distinct ortholog, was chosen to root the tree. Numbers on branches indicate the percentage of 1000 bootstrap replicates that support the adjacent node; Accession numbers: ProchMED4-Lb, NP_893181; Proch9312-Lb, YP_397570; Proch1375-Lb, NP_875528; ProchNATL2A-Lb, YP_291882; Proch9313-Lb, NP_894954; Syne9605-Lb, YP_382237; Syne8102-Lb, NP_896821; Syne7942-L, ZP_00165074; Syne6301-L, YP_172741; Syne9902-Lb, YP_376736; ProchNATL2A-Le, YP_291268; Proch1375-Le, NP_875182; Proch9313-Le, NP_895600; ProchMED4-Le, NP_892751; Proch9312-Le, YP_397130; H.pluv-Lb, AO64977; C. rein-Lb, AAX54906; C. rein-Le, AAT46065; A.thal-Lb, NP_187634; A.thal-Le, NP_200513; L. escu-Le, CAA74745; L.escu-Lb, CAA60170; C.sien-Lb, AAU05146; C.sien-Le, AAS48096, C.auran-L, ZP_00766039.

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Fig 4

Model of structure of lycopene cyclases from cyanobacteria and plants. A, The structure-model of β-lycopene cyclase from Prochlorococcus MIT9312; B, The structure-model of ε-lycopene cyclase from Prochlorococcus MIT9312; C, The structure-model of β-lycopene cyclase from Arabidopsis thaliana; D, The structure-model of ε-lycopene cyclase from Arabidopsis thaliana.

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Fig 5

Comparison of the amino acid sequence of fatty acid desaturases, β-hydroxylase and β-ketolase. The conserved H-boxes were in black. 'FAD' represents fatty acid desaturase; 'R' represents crtR; 'W' represents crtW. The sequence sources are as follow: Tri101-FAD ZP_00675708; Ana29413-FAD YP_324705; Syn6803-FAD NP_441489; Cro8501-R ZP_00514501; Syn6803-R NP_440788; Ana29413-R YP_322210; Ana7120-R, NP_488049; Syn7942-R, YP_401456; Thermo-R NP_682690; Pro9605-R YP_380617; Ana29413-W1 YP_322565; Ana7120-W NP_487229; Nos73102-W1 ZP_00111258; Glo7421-W NP_924674; Syn8102-W NP_897461; Syn9902-W YP_376982.

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Fig 6

Genomic organization of the crt genes potentially encoding enzymes involved in the carotene biosynthetic pathway of various cyanobacterial species. Long horizontal line indicates the chromosome, whereas short horizontal lines denote the extranuclear plasmids. Deduced chromosomal positions of the crt genes are marked by arrows with different colors. Arrows represent the direction of translation and the relative sizes of ORFs deduced from analysis of the nucleotide sequence. Note that C.watsonii WH8501 and T. erythraeum IMS 101 genomes were still in draft format, and crt genes were mapped onto the chromosome evenly. Gene names are given at the bottom of the figure.