Abstract
The streptococcal plasmid pMV158 encodes the relaxase protein, MobM, involved in its mobilisation. Purified MobM protein specifically cleaved supercoiled or single-stranded DNA containing the plasmid origin of transfer, oriT. Gel retardation and DNase I footprinting assays performed with DNA fragments containing the plasmid oriT provided evidence for specific binding of MobM by oriT DNA. Dissection of the MobM-binding sequence revealed that the oriT region protected by MobM spanned 28 nucleotides, and includes an inversely repeated sequence, termed IR2. MobM exhibits a high degree of similarity with the mob gene product of the Streptococcus ferus plasmid pVA380-1. Although the origins of transfer of pMV158 and pVA380-1 show 20% sequence divergence in a 24-bp sequence included in their oriT regions, the pMV158 MobM was able to cleave a supercoiled derivative of pVA380-1 in vitro.
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Received: 12 October 1998 / Accepted: 28 February 1999
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Grohmann, E., Guzmán, L. & Espinosa, M. Mobilisation of the streptococcal plasmid pMV158: interactions of MobM protein with its cognate oriT DNA region. Mol Gen Genet 261, 707–715 (1999). https://doi.org/10.1007/s004380050014
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DOI: https://doi.org/10.1007/s004380050014