Abstract
Tn5252is a promiscuous streptococcal element capable of madiating horizontal spread of multiple antibiotic resistance. To begin understanding the functional role of a transfer-related region in Tn5252,its nucleotide sequence was determined. Sequence of this 3.3-kb DNA segment revealed the presence of six open reading frames. The predicted amino acid sequence of one of the open reading frames, ORF9, showed similarity to a predicted protein product of the lactococcal conjugative plasmid, pC1528. The deduced primary protein sequence of another, ORF4, showed strong structural similarity to conserved regions of various prokaryotic DNA relaxases that initiate conjugal transfer by strand- and site-specific cleavage at the transfer origin. A hybrid protein containing the ORF4 protein fused to the carboxyl terminal end of maltose binding protein was purified fromEscherichia coliand found to specifically nick plasmids carrying a 2-kb DNA segment derived from the transposon. The nicking reaction is protein concentration-dependent. These results imply that the conjugative transposition of Tn5252may involve rolling circle replication and transfer of a unique DNA strand.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.