J Michael Sauder - Type VI secretion apparatus and phage tail-associated protein complexes share a common evolutionary origin

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      Publication Details (including relevant citation   information):

      Proc Natl Acad Sci USA (2009) 106: 4154-4159.

      Leiman PG, Basler M, Ramagopal UA, Bonanno JB, Sauder JM,   Pukatzki S, Burley SK, Almo SC, Mekalanos JJ


      Protein secretion is a common property of pathogenic   microbes.  Gram-negative bacterial pathogens use at least 6   distinct extracellular  protein secretion systems to export   proteins through their multilayered  cell envelope and in   some cases into host cells. Among the most  widespread is   the newly recognized Type VI secretion system (T6SS) which    is composed of 15-20 proteins whose biochemical functions are not   well  understood. Using crystallographic, biochemical, and   bioinformatic  analyses, we identified 3 T6SS components,   which are homologous to  bacteriophage tail proteins. These   include the tail tube protein; the  membrane-penetrating   needle, situated at the distal end of the tube; and  another   protein associated with the needle and tube. We propose   that  T6SS is a multicomponent structure whose extracellular   part resembles  both structurally and functionally a   bacteriophage tail, an efficient  machine that translocates   proteins and DNA across lipid membranes into  cells.

      Address (URL): http://www.pnas.org/content/106/11/4154.long