Structural biology of the Gram-negative bacterial conjugation systems

Trends Microbiol. 2015 May;23(5):301-10. doi: 10.1016/j.tim.2015.02.012. Epub 2015 Mar 27.

Abstract

Conjugation, the process by which plasmid DNA is transferred from one bacterium to another, is mediated by type IV secretion systems (T4SSs). T4SSs are versatile systems that can transport not only DNA, but also toxins and effector proteins. Conjugative T4SSs comprise 12 proteins named VirB1-11 and VirD4 that assemble into a large membrane-spanning exporting machine. Before being transported, the DNA substrate is first processed on the cytoplasmic side by a complex called the relaxosome. The substrate is then targeted to the T4SS for export into a recipient cell. In this review, we describe the recent progress made in the structural biology of both the relaxosome and the T4SS.

Keywords: DNA transport; T4SS; Type IV secretion system; bacterial conjugation; structural biology; substrate secretion.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Bacterial Outer Membrane Proteins / metabolism*
  • Conjugation, Genetic*
  • DNA, Bacterial / metabolism
  • Gram-Negative Bacteria / genetics*
  • Gram-Negative Bacteria / metabolism
  • Models, Molecular
  • Plasmids
  • Type IV Secretion Systems / chemistry*
  • Type IV Secretion Systems / genetics
  • Type IV Secretion Systems / physiology*

Substances

  • Bacterial Outer Membrane Proteins
  • DNA, Bacterial
  • Type IV Secretion Systems