期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2007
卷号：104
期号：12
页码：5127-5132
DOI：10.1073/pnas.0700429104
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：More than a dozen large DNA viruses exceeding 240-kb genome size were recently discovered, including the "giant" mimivirus with a 1.2-Mb genome size. The detection of mimivirus and other large viruses has stimulated new analysis and discussion concerning the early evolution of life and the complexity and mechanisms of evolutionary transitions. This paper presents analysis in three contexts. (i) Genome signatures of large viruses tend to deviate from the genome signatures of their hosts, perhaps indicating that the large viruses are lytic in the hosts. (ii) Proteome composition within these viral genomes contrast with cellular organisms; for example, most eukaryotic genomes, with respect to acidic residue usages, select Glu over Asp, but the opposite generally prevails for the large viral genomes preferring Asp more than Glu. In comparing Phe vs. Tyr usage, the viral genomes select mostly Tyr over Phe, whereas in almost all bacterial and eukaryotic genomes, Phe is used more than Tyr. Interpretations of these contrasts are proffered with respect to protein structure and function. (iii) Frequent oligonucleotides and peptides are characterized in the large viral genomes. The frequent words may provide structural flexibility to interact with host proteins.
关键词：mimivirus ; genome signature ; frequent oligonucleotides and peptides
