MBIO 4600 Lecture Notes - Lecture 30: Pilus, Secretion, Type Three Secretion System
25 Dec 2015
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Document Summary
All systems rely on channels in the outer membrane formed from beta-sheets organized in a ring. Type iv (t4ss: ancestrally related to conjugation systems. P-t4ss (a. tumefaciens t-dna) vir genes. I-t4ss (l. pneumophila) icm/dot genes: multi-subunit cell-envelope-spanning structures compromising a secretion channel and a pilus, transfer both proteins and nucleoprotein complexes. Delivery of bacterial effector proteins into eukaryotic host cells: a. tumefaciens. T4ss encoded by vir operon (11 genes) and vird4. Vir operon genes essential for dna transfer. Mediates transfer of oncogenic genes into plant cells. Vire3 pulls along ssdna: l. pneumophila. Bacterium core genome and flexible gene pool: is, transposons, plasmids, integrons, prophages, and large unstable regions (islands) Carry mobility genes (similar to int or transposases) Flanked on one side by a trna gene. 3" end sequence frequently identical to attb sites of phages. Act as recognition sequences for enzymes involved in excision.
