Complete genome structure of Gloeobacter violaceus PCC 7421, a cyanobacterium that lacks thylakoids
Complete genome structure of Gloeobacter violaceus PCC 7421, a cyanobacterium that lacks thylakoids
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DOI：
10.1093/dnares/10.4.137
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发表时间：
2003-08-31
期刊：
影响因子：
4.1
通讯作者：
Tabata, S
中科院分区：
文献类型：
--
作者：
Nakamura, Y;Kaneko, T;Tabata, S
测定了蓝细菌Gloeulum violaceus PCC 7421的全基因组的核苷酸序列。G.结果表明，该菌株为单环状染色体，长度为4，659，019 bp，GC含量平均为62%，未检测到质粒。该染色体包括4430个潜在的蛋白质编码基因、一组rRNA基因、代表44种tRNA的45个tRNA基因以及tmRNA、RNase P的B亚基、SRP RNA和6 Sa RNA的基因。41%的潜在蛋白质编码基因与已知功能的基因序列相似，37%与假设基因相似，其余22%与已报道的基因没有明显相似性。通过与其他蓝藻的基因组比较，揭示了G.紫罗兰基因组光系统I的PsaI、PsaJ、PsaK和PsaX以及光系统II的PsbY、PsbZ和Psb 27的基因缺失，而PsaF、PsbO、PsbU和PsbV的基因保守性较差。用于藻胆体的杆核接头肽的cpcG和与藻胆体降解相关的nblA也缺失。潜在的信号肽的假定产品的petJ和petE可溶性电子转移催化剂是不太保守的比其余部分。这些现象可能与G.紫色不发生在类囊体膜上，而发生在细胞质膜上。在LuxR、LysR、PadR、TetR和马尔R等5个基因家族中发现了大量的sigma因子和转录因子基因，但未发现生物钟主要元件kaiABC基因。violaceus和其他蓝细菌。
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.