Publication Date:
2012-06-16
Description:
Pathogenic bacteria using a type III secretion system (T3SS) to manipulate host cells cause many different infections including Shigella dysentery, typhoid fever, enterohaemorrhagic colitis and bubonic plague. An essential part of the T3SS is a hollow needle-like protein filament through which effector proteins are injected into eukaryotic host cells. Currently, the three-dimensional structure of the needle is unknown because it is not amenable to X-ray crystallography and solution NMR, as a result of its inherent non-crystallinity and insolubility. Cryo-electron microscopy combined with crystal or solution NMR subunit structures has recently provided a powerful hybrid approach for studying supramolecular assemblies, resulting in low-resolution and medium-resolution models. However, such approaches cannot deliver atomic details, especially of the crucial subunit-subunit interfaces, because of the limited cryo-electron microscopic resolution obtained in these studies. Here we report an alternative approach combining recombinant wild-type needle production, solid-state NMR, electron microscopy and Rosetta modelling to reveal the supramolecular interfaces and ultimately the complete atomic structure of the Salmonella typhimurium T3SS needle. We show that the 80-residue subunits form a right-handed helical assembly with roughly 11 subunits per two turns, similar to that of the flagellar filament of S. typhimurium. In contrast to established models of the needle in which the amino terminus of the protein subunit was assumed to be alpha-helical and positioned inside the needle, our model reveals an extended amino-terminal domain that is positioned on the surface of the needle, while the highly conserved carboxy terminus points towards the lumen.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3598588/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3598588/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Loquet, Antoine -- Sgourakis, Nikolaos G -- Gupta, Rashmi -- Giller, Karin -- Riedel, Dietmar -- Goosmann, Christian -- Griesinger, Christian -- Kolbe, Michael -- Baker, David -- Becker, Stefan -- Lange, Adam -- 1R01GM092802-01/GM/NIGMS NIH HHS/ -- R01 GM092802/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2012 May 20;486(7402):276-9. doi: 10.1038/nature11079.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Gottingen, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22699623" target="_blank"〉PubMed〈/a〉
Keywords:
*Bacterial Secretion Systems
;
HeLa Cells
;
Humans
;
Microscopy, Electron
;
*Models, Molecular
;
Nuclear Magnetic Resonance, Biomolecular
;
Protein Structure, Secondary
;
Salmonella typhimurium/*chemistry
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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