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Updated: Jul 30, 2026

Conjugative Mating Assays for Sequence-specific Analysis of Transfer Proteins Involved in Bacterial Conjugation
Published on: January 4, 2017
Relaxed specificity of the R1162 nickase: a model for evolution of a system for conjugative mobilization of plasmids
Eric C Becker1, Richard J Meyer
1Section of Molecular Genetics and Microbiology, Institute for Cellular and Molecular Biology, School of Biology, University of Texas at Austin, Austin, Texas 78712, USA.
Abstract:
The primary DNA processing protein for conjugative mobilization of the plasmid R1162 is the transesterase MobA, which acts at a unique site on the plasmid, the origin of transfer (oriT). Both MobA and oriT are members of a large family of related elements that are widely distributed among bacteria. Each oriT consists of a highly conserved core and an adjacent region that is required for binding by its cognate MobA. The sequence of the adjacent region is important in determining the specificity of the interaction between the Mob protein and the oriT DNA. However, the R1162 MobA is active on the oriT of pSC101, another naturally occurring plasmid. We show here that MobA can recognize oriTs having different sequences in the adjacent region and, with varying frequencies, can cleave these oriTs at the correct position within the core. Along with the structure of the oriTs themselves, these characteristics suggest a model for the evolution of this group of transfer systems.
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