Journal Article

Complete Genome Structure of <i>Gloeobacter violaceus</i> PCC 7421, a Cyanobacterium that Lacks Thylakoids

Yasukazu Nakamura, Takakazu Kaneko, Shusei Sato, Mamoru Mimuro, Hideaki Miyashita, Tohru Tsuchiya, Shigemi Sasamoto, Akiko Watanabe, Kumiko Kawashima, Yoshie Kishida, Chiaki Kiyokawa, Mitsuyo Kohara, Midori Matsumoto, Ai Matsuno, Naomi Nakazaki, Sayaka Shimpo, Chie Takeuchi, Manabu Yamada and Satoshi Tabata

in DNA Research

Published on behalf of Kazusa DNA Research Institute

Volume 10, issue 4, pages 137-145
Published in print January 2003 | ISSN: 1340-2838
Published online January 2003 | e-ISSN: 1756-1663 | DOI: http://dx.doi.org/10.1093/dnares/10.4.137

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The nucleotide sequence of the entire genome of a cyanobacterium Gloeobacter violaceus PCC 7421 was determined. The genome of G. violaceus was a single circular chromosome 4,659,019 bp long with an average GC content of 62%. No plasmid was detected. The chromosome comprises 4430 potential protein-encoding genes, one set of rRNA genes, 45 tRNA genes representing 44 tRNA species and genes for tmRNA, B subunit of RNase P, SRP RNA and 6Sa RNA. Forty-one percent of the potential protein-encoding genes showed sequence similarity to genes of known function, 37% to hypothetical genes, and the remaining 22% had no apparent similarity to reported genes. Comparison of the assigned gene components with those of other cyanobacteria has unveiled distinctive features of the G. violaceus genome. Genes for PsaI, PsaJ, PsaK, and PsaX for Photosystem I and PsbY, PsbZ and Psb27 for Photosystem II were missing, and those for PsaF, PsbO, PsbU, and PsbV were poorly conserved. cpcG for a rod core linker peptide for phycobilisomes and nblA related to the degradation of phycobilisomes were also missing. Potential signal peptides of the presumptive products of petJ and petE for soluble electron transfer catalysts were less conserved than the remaining portions. These observations may be related to the fact that photosynthesis in G. violaceus takes place not in thylakoid membranes but in the cytoplasmic membrane. A large number of genes for sigma factors and transcription factors in the LuxR, LysR, PadR, TetR, and MarR families could be identified, while those for major elements for circadian clock, kaiABC were not found. These differences may reflect the phylogenetic distance between G. violaceus and other cyanobacteria.

Keywords: cyanobacterium; Gloeobacter violaceus; thylakoid membranes; genomic sequencing

Journal Article.  0 words. 

Subjects: Genetics and Genomics

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