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. 2019 Apr 5;7(2):10.1128/microbiolspec.psib-0012-2018. doi: 10.1128/microbiolspec.psib-0012-2018

FIGURE 1.

FIGURE 1

Functional and compositional diversity of the bacterial type IV secretion systems (T4SSs). (A) (Left) Contact-dependent conjugation systems and recently described killing systems deliver DNA or protein substrates directly to bacterial target cells. Contact-independent systems mediate DNA import, DNA export, or export of the multimeric pertussis toxin. (Right) Various pathogenic bacteria and symbionts have evolved T4SSs to deliver effector proteins or DNA-protein complexes into eukaryotic host cells to subvert host physiological processes. (B) Gene arrangements and architectures of the A. tumefaciens VirB/VirD4 and L. pneumophila Dot/Icm secretion systems, with color-coding of the genes encoding homologous subunits; unshaded genes are unique to the Dot/Icm system. The VirB/VirD4 subunit enzymatic functions and associations with inner membrane complex (IMC), outer membrane core complex (OMCC), or pilus are listed. PG Hydrolase, peptidoglycan hydrolase; T4CP, type IV coupling protein.