Genome sequence of Haloarcula marismortui:: A halophilic archaeon from the Dead Sea
Genome sequence of Haloarcula marismortui:: A halophilic archaeon from the Dead Sea
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DOI：
10.1101/gr.2700304
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发表时间：
2004-11-01
期刊：
影响因子：
7
通讯作者：
Ng, WV
中科院分区：
文献类型：
--
作者：
Baliga, NS;Bonneau, R;Ng, WV
我们报告了来自死海的嗜盐古菌Haloarcula marismortui的4，274，642-bp基因组的完整序列。基因组被组织成9个环状复制子，其G+C组成从54%到62%不等。盐杆菌NRC-1和H. marismortui表明这两种生物有一个共同的祖先，前者的基因组明显缩小。这两种嗜盐古菌都使用相同的策略，即折叠蛋白质的高表面负电荷作为规避高盐细胞质中盐析现象的手段。一个多层次的注释方法，包括一级序列相似性，蛋白质家族的签名，结构预测，和蛋白质功能关联网络，已分配推定的功能，至少58%的4242预测的蛋白质，远大于通常在大多数新测序的微生物。在这些指定的功能中，有编码6种视蛋白、19种MCP和/或HAMP结构域信号转导子的基因，以及异常大量的环境反应调节剂--几乎是盐杆菌NRC-1中编码的调节剂的五倍--这表明H. marismortui在生理上更有能力利用不同的环境。在比较两个嗜盐古菌的生理，除了预期的广泛的相似性，我们发现他们的代谢策略和生理反应，如不同的途径精氨酸分解在每个嗜盐菌的几个差异。最后，正如对更大基因组的预期，H. marismortul编码更多的功能，并且似乎比盐杆菌NRC-1具有更少的生存营养需求。
We report the complete sequence of the 4,274,642-bp genome of Haloarcula marismortui, a halophilic archaeal isolate from the Dead Sea. The genome is organized into nine circular replicons of varying G+C compositions ranging from 54% to 62%. Comparison of the genome architectures of Halobacterium sp. NRC-1 and H. marismortui suggests a common ancestor for the two organisms and a genome of significantly reduced size in the former. Both of these halophilic archaea use the same strategy of high surface negative charge of folded proteins as means to circumvent the salting-out phenomenon in a hypersaline cytoplasm. A multitiered annotation approach, including primary sequence similarities, protein family signatures, structure prediction, and a protein function association network, has assigned putative functions for at least 58% of the 4242 predicted proteins, a far larger number than is usually achieved in most newly sequenced microorganisms. Among these assigned functions were genes encoding six opsins, 19 MCP and/or HAMP domain signal transducers, and an unusually large number of environmental response regulators-nearly five times as many as those encoded in Halobacterium sp. NRC-1-suggesting H. marismortui is significantly more physiologically capable of exploiting diverse environments. In comparing the physiologles of the two halophilic archaea, in addition to the expected extensive similarity, we discovered several differences in their metabolic strategies and physiological responses such as distinct pathways for arginine breakdown in each halophile. Finally, as expected from the larger genome, H. marismortul encodes many more functions and seems to have fewer nutritional requirements for survival than does Halobacterium sp. NRC-1.