Complete genome structure of the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1.
The entire genome of a thermophilic unicellular cyanobacterium, Thermosynechococcus elongatus BP-1, was sequenced. The genome consisted of a circular chromosome 2,593,857 bp long, and no plasmid was detected. A total of 2475 potential protein-encoding genes, one set of rRNA genes, 42 tRNA genes representing 42 tRNA species and 4 genes for small structural RNAs were assigned to the chromosome by similarity search and computer prediction. The translated products of 56% of the potential protein-encoding genes showed sequence similarity to experimentally identified and predicted proteins of known function, and the products of 34% of these genes showed sequence similarity to the translated products of hypothetical genes. The remaining 10% lacked significant similarity to genes for predicted proteins in the public DNA databases. Sixty-three percent of the T. elongatus genes showed significant sequence similarity to those of both Synechocystis sp. PCC 6803 and Anabaena sp. PCC 7120, while 22% of the genes were unique to this species, indicating a high degree of divergence of the gene information among cyanobacterial strains. The lack of genes for typical fatty acid desaturases and the presence of more genes for heat-shock proteins in comparison with other mesophilic cyanobacteria may be genomic features of thermophilic strains. A remarkable feature of the genome is the presence of 28 copies of group II introns, 8 of which contained a presumptive gene for maturase/reverse transcriptase. A trace of genome rearrangement mediated by the group II introns was also observed.
Nakamura
Yasukazu
Y
Kazusa DNA Research Institute, Kisarazu, Chiba, Japan.
Kaneko
Takakazu
T
Sato
Shusei
S
Ikeuchi
Masahiko
M
Katoh
Hiroshi
H
Sasamoto
Shigemi
S
Watanabe
Akiko
A
Iriguchi
Mayumi
M
Kawashima
Kumiko
K
Kimura
Takaharu
T
Kishida
Yoshie
Y
Kiyokawa
Chiaki
C
Kohara
Mitsuyo
M
Matsumoto
Midori
M
Matsuno
Ai
A
Nakazaki
Naomi
N
Shimpo
Sayaka
S
Sugimoto
Masako
M
Takeuchi
Chie
C
Yamada
Manabu
M
Tabata
Satoshi
S
D000458:Cyanobacteria / Q000235:genetics* / Q000378:metabolism; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D010788:Photosynthesis / Q000235:genetics; D017422:Sequence Analysis, DNA