Yang Grace Li, Annika Breidenstein, Ronnie P-A Berntsson, Peter J Christie
{"title":"Conjugative transfer of the IncN plasmid pKM101 is mediated by dynamic interactions between the TraK accessory factor and TraI relaxase.","authors":"Yang Grace Li, Annika Breidenstein, Ronnie P-A Berntsson, Peter J Christie","doi":"10.1002/1873-3468.15011","DOIUrl":null,"url":null,"abstract":"<p><p>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 (TraI<sub>CTD</sub>) wraps around TraK's C-proximal tetramerization domain. Upon relaxosome assembly, conformational changes disrupt this contact, and TraI<sub>CTD</sub> 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.</p>","PeriodicalId":12142,"journal":{"name":"FEBS Letters","volume":null,"pages":null},"PeriodicalIF":3.5000,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"FEBS Letters","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1002/1873-3468.15011","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"Biochemistry, Genetics and Molecular Biology","Score":null,"Total":0}
引用次数: 0
Abstract
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.
期刊介绍:
FEBS Letters is one of the world''s leading journals in molecular biology and is renowned both for its quality of content and speed of production. Bringing together the most important developments in the molecular biosciences, FEBS Letters provides an international forum for Minireviews, Research Letters and Hypotheses that merit urgent publication.