The structure of the Salmonella typhimurium type III secretion system needle shows divergence from the flagellar system.
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The structure of the Salmonella typhimurium type III secretion system needle shows divergence from the flagellar system. / Galkin, Vitold E; Schmied, Wolfgang H; Schraidt, Oliver; Marlovits, Thomas; Egelman, Edward H.
in: J MOL BIOL, Jahrgang 396, Nr. 5, 5, 2010, S. 1392-1397.Publikationen: SCORING: Beitrag in Fachzeitschrift/Zeitung › SCORING: Zeitschriftenaufsatz › Forschung › Begutachtung
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T1 - The structure of the Salmonella typhimurium type III secretion system needle shows divergence from the flagellar system.
AU - Galkin, Vitold E
AU - Schmied, Wolfgang H
AU - Schraidt, Oliver
AU - Marlovits, Thomas
AU - Egelman, Edward H
PY - 2010
Y1 - 2010
N2 - The type III secretion system (T3SS) is essential for the infectivity of many pathogenic Gram-negative bacteria. The T3SS contains proteins that form a channel in the inner and outer bacterial membranes, as well as an extracellular needle that is used for transporting and injecting effector proteins into a host cell. The homology between the T3SS and the bacterial flagellar system has been firmly established, based upon both sequence similarities between respective proteins in the two systems and the structural homology of higher-order assemblies. It has previously been shown that the Shigella flexneri needle has a helical symmetry of approximately 5.6 subunits/turn, which is quite similar to that of the most intensively studied flagellar filament (from Salmonella typhimurium), which has approximately 5.5 subunits/turn. We now show that the Sa. typhimurium needle, expected by homology arguments to be more similar to the Sa. typhimurium flagellar filament than is the needle from Shigella, actually has approximately 6.3 subunits/turn. It is not currently understood how host cell contact, made at the tip of the needle, is communicated to the secretory system at the base. In contrast to the Sa. typhimurium flagellar filament, which shows a nearly crystalline order, the Sa. typhimurium needle has a highly variable symmetry, which could be used to transmit information about host cell contact.
AB - The type III secretion system (T3SS) is essential for the infectivity of many pathogenic Gram-negative bacteria. The T3SS contains proteins that form a channel in the inner and outer bacterial membranes, as well as an extracellular needle that is used for transporting and injecting effector proteins into a host cell. The homology between the T3SS and the bacterial flagellar system has been firmly established, based upon both sequence similarities between respective proteins in the two systems and the structural homology of higher-order assemblies. It has previously been shown that the Shigella flexneri needle has a helical symmetry of approximately 5.6 subunits/turn, which is quite similar to that of the most intensively studied flagellar filament (from Salmonella typhimurium), which has approximately 5.5 subunits/turn. We now show that the Sa. typhimurium needle, expected by homology arguments to be more similar to the Sa. typhimurium flagellar filament than is the needle from Shigella, actually has approximately 6.3 subunits/turn. It is not currently understood how host cell contact, made at the tip of the needle, is communicated to the secretory system at the base. In contrast to the Sa. typhimurium flagellar filament, which shows a nearly crystalline order, the Sa. typhimurium needle has a highly variable symmetry, which could be used to transmit information about host cell contact.
KW - Models, Molecular
KW - Protein Multimerization
KW - Cryoelectron Microscopy
KW - Bacterial Proteins/chemistry/physiology/ultrastructure
KW - Flagella/chemistry/ultrastructure
KW - Microscopy, Electron, Scanning Transmission
KW - Multiprotein Complexes/chemistry/ultrastructure
KW - Salmonella typhimurium/chemistry/physiology/ultrastructure
KW - Shigella flexneri/chemistry/ultrastructure
KW - Models, Molecular
KW - Protein Multimerization
KW - Cryoelectron Microscopy
KW - Bacterial Proteins/chemistry/physiology/ultrastructure
KW - Flagella/chemistry/ultrastructure
KW - Microscopy, Electron, Scanning Transmission
KW - Multiprotein Complexes/chemistry/ultrastructure
KW - Salmonella typhimurium/chemistry/physiology/ultrastructure
KW - Shigella flexneri/chemistry/ultrastructure
M3 - SCORING: Journal article
VL - 396
SP - 1392
EP - 1397
JO - J MOL BIOL
JF - J MOL BIOL
SN - 0022-2836
IS - 5
M1 - 5
ER -