Conjugative transfer of the IncN plasmid pKM101 is mediated by dynamic interactions between the TraK accessory factor and TraI relaxase

Li, Yang GraceDepartment of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth Houston, TX, United States (författare)

Conjugative dissemination of mobile genetic elements (MGEs) among bacteria is initiated by assembly of the relaxosome at the MGE's origin-of-transfer (oriT) sequence. A critical but poorly defined step of relaxosome assembly involves recruitment of the catalytic relaxase to its DNA strand-specific nicking site within oriT. Here, we present evidence by AlphaFold modeling, affinity pulldowns, and in vivo site-directed photocrosslinking that the TraK Ribbon–Helix–Helix DNA-binding protein recruits TraI to oriT through a dynamic interaction in which TraI's C-terminal unstructured domain (TraICTD) wraps around TraK's C-proximal tetramerization domain. Upon relaxosome assembly, conformational changes disrupt this contact, and TraICTD instead self-associates as a prerequisite for relaxase catalytic functions or substrate engagement with the transfer channel. These findings delineate key early-stage processing reactions required for conjugative dissemination of a model MGE.

NATURVETENSKAP Biologi Biokemi och molekylärbiologi hsv//swe
NATURAL SCIENCES Biological Sciences Biochemistry and Molecular Biology hsv//eng
antibiotic resistance
conjugation
horizontal DNA transfer
mobile genetic elements
relaxase
type IV secretion

Breidenstein, AnnikaUmeå universitet,Institutionen för medicinsk kemi och biofysik,Umeå Centre for Microbial Research (UCMR),Wallenberg centrum för molekylär medicin vid Umeå universitet (WCMM)(Swepub:umu)anbr0330 (författare)
Berntsson, Ronnie P.-A.Umeå universitet,Institutionen för medicinsk kemi och biofysik,Umeå Centre for Microbial Research (UCMR),Wallenberg centrum för molekylär medicin vid Umeå universitet (WCMM)(Swepub:umu)robe0049 (författare)
Christie, Peter J.Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth Houston, TX, United States (författare)
Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth Houston, TX, United StatesInstitutionen för medicinsk kemi och biofysik (creator_code:org_t)

Av författaren/redakt...: Li, Yang Grace; Breidenstein, An ...; Berntsson, Ronni ...; Christie, Peter ...

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