RESUMO
Bacteriophage PM2 was isolated from the Pacific Ocean off the coast of Chile in the late 1960s. It was a new virus type, later classified as Corticoviridae, and also the first bacterial virus for which it was demonstrated that lipids are part of the virion structure. Here we report the determination and analysis of the 10, 079-bp circular dsDNA genome sequence. Noteworthy discoveries are the replication initiation system, which is related to the rolling circle mechanism described for phages such as φX174 and P2, and a 1.2-kb sequence that is similar to the maintenance region of a plasmid found in a marine Pseudoalteromonas sp. strain A28.
Assuntos
Corticoviridae/química , Corticoviridae/genética , Proteínas de Ligação a DNA , Genoma Viral , Lipídeos/análise , Sequência de Aminoácidos , Sequência de Bases , Corticoviridae/crescimento & desenvolvimento , Corticoviridae/isolamento & purificação , DNA Helicases/química , DNA Helicases/genética , DNA Helicases/fisiologia , Replicação do DNA/genética , Genes Virais/genética , Genes Virais/fisiologia , Bactérias Gram-Negativas/virologia , Dados de Sequência Molecular , Fases de Leitura Aberta/genética , Óperon/genética , Plasmídeos/genética , Origem de Replicação/genética , Mapeamento por Restrição , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , Transativadores/química , Transativadores/genética , Transativadores/fisiologia , Proteínas Estruturais Virais/química , Proteínas Estruturais Virais/genéticaRESUMO
The marine, icosahedral bacteriophage PM2 was isolated in the late 1960s. It was the first phage for which lipids were firmly demonstrated to be part of the virion structure and it has been classified as the type organism of the Corticoviridae family. The host, Pseudoalteromonas espejiana BAL-31, belongs to a common group of marine bacteria. We developed a purification method producing virions with specific infectivity approximately as high as that of the lipid-containing phages PRD1 and φ6. The sensitivity of the virus to normally used purification media such as those containing sucrose is demonstrated. We also present an alternative host, a pseudoalteromonad, that allows enhanced purification of the virus under reduced salt conditions. We show, using N-terminal amino acid sequencing and comparison with the genomic sequence, that there are at least eight structural proteins in the infectious virus.
