Evolutionary link between the mycobacterial plasmid pAL5000 replication protein RepB and the extracytoplasmic function family of σ factors.

ABSTRACT: Mycobacterial plasmid pAL5000 represents a family of plasmids found mostly in the Actinobacteria. It replicates using two plasmid-encoded proteins, RepA and RepB. While BLAST searches indicate that RepA is a replicase family protein, the evolutionary connection of RepB cannot be established, as no significant homologous partner (E < 10(-3)) outside the RepB family can be identified. To obtain insight into the structure-function and evolutionary connections of RepB, an investigation was undertaken using homology modeling, phylogenetic, and mutational analysis methods. The results indicate that although they are synthesized from the same operon, the phylogenetic affinities of RepA and RepB differ. Thus, the operon may have evolved through random breaking and joining events. Homology modeling

SUBMITTER: Basu A 

PROVIDER: S-EPMC3294839 | biostudies-literature | 2012 Mar

REPOSITORIES: biostudies-literature