Differences in the Electrostatic Surfaces of the Type III Secretion Needle Proteins PrgI, BsaL, and MxiH

Wang, Yu; Ouellette, A.N.; Egan, Chet; Rathinavelan, Thenmalarchelvi; Im, Wonpil; Guzman, Roberto N. De

doi:10.1016/j.jmb.2007.06.034

Cited by 61 publications

(97 citation statements)

References 42 publications

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“…Because the 3D map allowed the identification of correspondences with secondary structural elements of the MxiH crystal structure, we tried to fit the MxiH "head" (residues 26-51), including the short ProSer-Asn-Pro (PSNP; residues 41-44) loop into the map. The conformation of this portion is nearly the same in all the NMR and X-ray structures of monomeric proteins available for this protein family (12,13,18,19) (Fig. S1).…”

Section: Resultsmentioning

confidence: 87%

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Structure of a type III secretion needle at 7-Å resolution provides insights into its assembly and signaling mechanisms

Fujii

Cheung

Blanco

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

114

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Type III secretion systems of Gram-negative bacteria form injection devices that deliver effector proteins into eukaryotic cells during infection. They span both bacterial membranes and the extracellular space to connect with the host cell plasma membrane. Their extracellular portion is a needle-like, hollow tube that serves as a secretion conduit for effector proteins. The needle of Shigella flexneri is approximately 50-nm long and 7-nm thick and is made by the helical assembly of one protein, MxiH. We provide a 7-Å resolution 3D image reconstruction of the Shigella needle by electron cryomicroscopy, which resolves α-helices and a β-hairpin that has never been observed in the crystal and solution structures of needle proteins, including MxiH. An atomic model of the needle based on the 3D-density map, in comparison with that of the bacterial-flagellar filament, provides insights into how such a thin tubular structure is stably assembled by intricate intermolecular interactions. The map also illuminates how the needle-length control protein functions as a ruler within the central channel during export of MxiH for assembly at the distal end of the needle, and how the secretion-activation signal may be transduced through a conformational change of the needle upon host-cell contact.helical image analysis | Shigella pathogenesis | bacterial protein secretion

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Section: Resultsmentioning

confidence: 87%

“…However, none of the available atomic models of MxiH and its homologs ( Fig. S1) (12,13,18,19) can be fitted into our density map.…”

Section: Resultsmentioning

confidence: 99%

Structure of a type III secretion needle at 7-Å resolution provides insights into its assembly and signaling mechanisms

Fujii

Cheung

Blanco

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

114

View full text Add to dashboard Cite

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“…However, these studies did not specifically determine whether InvJ was required for the assembly of the inner rod or for its anchoring to the base. The atomic structure of the inner rod subunit PrgJ is predicted to share very substantial structural similarities with PrgI, the needle subunit (19)(20)(21). Indeed, the in silico-modeled structures of PrgJ and PrgI share a similar α-helical hairpin shape flanked by flexible regions, and the two monomeric structures align very well around critical domains required for needle assembly (Fig.…”

Section: Resultsmentioning

confidence: 98%

The inner rod protein controls substrate switching and needle length in a Salmonella type III secretion system

Lefebre

Galán

2013

Proc. Natl. Acad. Sci. U.S.A.

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Type III secretion machines are essential for the biology of many bacteria that are pathogenic or symbiotic for animals, plants, or insects. They exert their function by delivering bacterial effector proteins into target eukaryotic cells. The core component of these machines is the needle complex, a multiprotein structure that spans the bacterial envelope and serves as a conduit for proteins that transit this secretion pathway. The needle complex is composed of a multiring base embedded in the bacterial envelope and a filament-like structure, the needle, that projects from the bacterial surface and is linked to the base by the inner rod. Assembly of the needle complex proceeds in a step-wise fashion that is initiated by the assembly of the base and is followed by the export of the building subunits for the needle and inner rod substructures. Once assembled, the needle complex reprograms its specificity and becomes competent for the secretion of effector proteins. Here through genetic, biochemical, and electron microscopy analyses of the Salmonella inner rod protein subunit PrgJ we present evidence that the assembly of the inner rod dictates the timing of substrate switching and needle length. Furthermore, the identification of mutations in PrgJ that specifically alter the hierarchy of protein secretion provides additional support for a complex role of the inner rod substructure in type III secretion.bacterial pathogenesis | organelle assembly | Salmonella pathogenesis

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“…1C). CdsF does lack the P-(S/D)-(D/N)-P turn, a four-residue ordered-loop region conserved among many other characterized needle proteins (12,30,61). However, this conservation is not complete, and the motif is only partially present, for example, in EscF of E. coli, PscF of Pseudomonas spp., and SsaH from Salmonella SPI-2 (63).…”

Section: Discussionmentioning

confidence: 99%

Bioinformatic and Biochemical Evidence for the Identification of the Type III Secretion System Needle Protein ofChlamydia trachomatis

et al. 2008

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Chlamydia spp. express a functional type III secretion system (T3SS) necessary for pathogenesis and intracellular growth. However, certain essential components of the secretion apparatus have diverged to such a degree as to preclude their identification by standard homology searches of primary protein sequences. One example is the needle subunit protein. Electron micrographs indicate that chlamydiae possess needle filaments, and yet database searches fail to identify a SctF homologue. We used a bioinformatics approach to identify a likely needle subunit protein for Chlamydia. Experimental evidence indicates that this protein, designated CdsF, has properties consistent with it being the major needle subunit protein. CdsF is concentrated in the outer membrane of elementary bodies and is surface exposed as a component of an extracellular needle-like projection. During infection CdsF is detectible by indirect immunofluorescence in the inclusion membrane with a punctuate distribution adjacent to membrane-associated reticulate bodies. Biochemical cross-linking studies revealed that, like other SctF proteins, CdsF is able to polymerize into multisubunit complexes. Furthermore, we identified two chaperones for CdsF, termed CdsE and CdsG, which have many characteristics of the Pseudomonas spp. needle chaperones PscE and PscG, respectively. In aggregate, our data are consistent with CdsF representing at least one component of the extended Chlamydia T3SS injectisome. The identification of this secretion system component is essential for studies involving ectopic reconstitution of the Chlamydia T3SS. Moreover, we anticipate that CdsF could serve as an efficacious target for anti-Chlamydia neutralizing antibodies.

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Differences in the Electrostatic Surfaces of the Type III Secretion Needle Proteins PrgI, BsaL, and MxiH

Cited by 61 publications

References 42 publications

Structure of a type III secretion needle at 7-Å resolution provides insights into its assembly and signaling mechanisms

Structure of a type III secretion needle at 7-Å resolution provides insights into its assembly and signaling mechanisms

The inner rod protein controls substrate switching and needle length in a Salmonella type III secretion system

Bioinformatic and Biochemical Evidence for the Identification of the Type III Secretion System Needle Protein ofChlamydia trachomatis

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