Two OB-fold proteins from a Gram-positive conjugative element engage in relaxosome assembly and DNA processing.

ABSTRACT: Integrative and conjugative elements (ICEs) are widespread genomic islands that propagate by bacterial conjugation. ICEs often spread antibiotic resistance genes and other adaptive genes conferring evolutionary advantages to their hosts. At the initiation of conjugation, the ICE DNA is processed by the relaxase, a transesterase that recognises its origin-of-transfer. ICESt3/Tn916/ICEBs1 superfamily of ICEs is widespread in Gram-positive bacteria, and it encodes uncanonical relaxases classified within the unique MOBT family. This study elucidates the roles of OrfL and OrfM, two OB-fold proteins from ICESt3, in its conjugative transfer. We demonstrated that OrfL and OrfM form a complex and function as relaxosomal auxiliary proteins with RelSt3, the ICESt3 MOBT relaxase. Through conjugation a

SUBMITTER: Laroussi H 

PROVIDER: S-EPMC12614216 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature