Structural and Functional Studies on the N-terminal Domain of the Shigella Type III Secretion Protein MxiG
MxiG is a single-pass membrane protein that oligomerizes within the inner membrane ring of the Shigella flexneri type III secretion system (T3SS). The MxiG N-terminal domain (MxiG-N) is the predominant cytoplasmic structure; however, its role in T3SS assembly and secretion is largely uncharacterized...
| Main Authors: | , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2011
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| _version_ | 1797055695233744896 |
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| author | McDowell, M Johnson, S Deane, J Cheung, M Roehrich, A Blocker, A McDonnell, J Lea, S |
| author_facet | McDowell, M Johnson, S Deane, J Cheung, M Roehrich, A Blocker, A McDonnell, J Lea, S |
| author_sort | McDowell, M |
| collection | OXFORD |
| description | MxiG is a single-pass membrane protein that oligomerizes within the inner membrane ring of the Shigella flexneri type III secretion system (T3SS). The MxiG N-terminal domain (MxiG-N) is the predominant cytoplasmic structure; however, its role in T3SS assembly and secretion is largely uncharacterized. We have determined the solution structure of MxiG-N residues 6-112 (MxiG-N(6-112)), representing the first published structure of this T3SS domain. The structure shows strong structural homology to forkhead-associated (FHA) domains. Canonically, these cell-signaling modules bind phosphothreonine (Thr(P)) via highly conserved residues. However, the putative phosphate-binding pocket of MxiG-N(6-112) does not align with other FHA domain structures or interact with Thr(P). Furthermore, mutagenesis of potential phosphate-binding residues has no effect on S. flexneri T3SS assembly and function. Therefore, MxiG-N has a novel function for an FHA domain. Positioning of MxiG-N(6-112) within the EM density of the S. flexneri needle complex gives insight into the ambiguous stoichiometry of the T3SS, supporting models with 24 MxiG subunits in the inner membrane ring. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc. |
| first_indexed | 2024-03-06T19:13:28Z |
| format | Journal article |
| id | oxford-uuid:178e518d-7e2f-485a-a3fe-60b80f733fbd |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T19:13:28Z |
| publishDate | 2011 |
| record_format | dspace |
| spelling | oxford-uuid:178e518d-7e2f-485a-a3fe-60b80f733fbd2022-03-26T10:38:03ZStructural and Functional Studies on the N-terminal Domain of the Shigella Type III Secretion Protein MxiGJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:178e518d-7e2f-485a-a3fe-60b80f733fbdEnglishSymplectic Elements at Oxford2011McDowell, MJohnson, SDeane, JCheung, MRoehrich, ABlocker, AMcDonnell, JLea, SMxiG is a single-pass membrane protein that oligomerizes within the inner membrane ring of the Shigella flexneri type III secretion system (T3SS). The MxiG N-terminal domain (MxiG-N) is the predominant cytoplasmic structure; however, its role in T3SS assembly and secretion is largely uncharacterized. We have determined the solution structure of MxiG-N residues 6-112 (MxiG-N(6-112)), representing the first published structure of this T3SS domain. The structure shows strong structural homology to forkhead-associated (FHA) domains. Canonically, these cell-signaling modules bind phosphothreonine (Thr(P)) via highly conserved residues. However, the putative phosphate-binding pocket of MxiG-N(6-112) does not align with other FHA domain structures or interact with Thr(P). Furthermore, mutagenesis of potential phosphate-binding residues has no effect on S. flexneri T3SS assembly and function. Therefore, MxiG-N has a novel function for an FHA domain. Positioning of MxiG-N(6-112) within the EM density of the S. flexneri needle complex gives insight into the ambiguous stoichiometry of the T3SS, supporting models with 24 MxiG subunits in the inner membrane ring. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc. |
| spellingShingle | McDowell, M Johnson, S Deane, J Cheung, M Roehrich, A Blocker, A McDonnell, J Lea, S Structural and Functional Studies on the N-terminal Domain of the Shigella Type III Secretion Protein MxiG |
| title | Structural and Functional Studies on the N-terminal Domain of the Shigella Type III Secretion Protein MxiG |
| title_full | Structural and Functional Studies on the N-terminal Domain of the Shigella Type III Secretion Protein MxiG |
| title_fullStr | Structural and Functional Studies on the N-terminal Domain of the Shigella Type III Secretion Protein MxiG |
| title_full_unstemmed | Structural and Functional Studies on the N-terminal Domain of the Shigella Type III Secretion Protein MxiG |
| title_short | Structural and Functional Studies on the N-terminal Domain of the Shigella Type III Secretion Protein MxiG |
| title_sort | structural and functional studies on the n terminal domain of the shigella type iii secretion protein mxig |
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