ingest cdrApp 2019-01-04T15:27:33.060Z 2a9effba-8beb-4434-9ac1-3dd15c1ac330 modifyDatastreamByValue RELS-EXT fedoraAdmin 2019-01-04T15:28:30.514Z Setting exclusive relation addDatastream MD_TECHNICAL fedoraAdmin 2019-01-04T15:28:43.127Z Adding technical metadata derived by FITS addDatastream MD_FULL_TEXT fedoraAdmin 2019-01-04T15:29:08.691Z Adding full text metadata extracted by Apache Tika modifyDatastreamByValue RELS-EXT fedoraAdmin 2019-01-04T15:29:33.798Z Setting exclusive relation modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2019-01-22T15:59:24.367Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2019-02-28T00:09:45.028Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2019-03-19T19:28:11.141Z Brittany Miller Author Department of Microbiology and Immunology School of Medicine Identification of a Chaperone for the SecA2 Protein Export Pathway of Mycobacterium tuberculosis The bacterial pathogen Mycobacterium tuberculosis is responsible for the disease tuberculosis. To promote disease, M. tuberculosis exports proteins from the cytoplasm to the bacterial cell surface or out into the host environment. Exported proteins are in an ideal location to manipulate the host. All bacteria, including mycobacteria, utilize the Sec export system for the bulk of protein export. The Sec system is composed of an ATPase protein, SecA, and a membrane channel complex, SecYEG. Mycobacteria, along with some Gram-positive bacteria, contain a second, functionally distinct paralog of the SecA protein. In mycobacteria, the SecA responsible for housekeeping export is called SecA1 and is essential for bacterial survival, while the second SecA is called SecA2 and exports a smaller subset of proteins and is important for M. tuberculosis virulence. The mechanism of SecA2-dependent export is not well understood. Past data support a model where the mycobacterial SecA2 export pathway is integrated into the housekeeping Sec pathway, and SecA2 shares use of the same SecYEG channel as SecA1 to export its substrates. Like SecA1, SecA2 requires ATPase activity to function. In this dissertation, we take the approach of characterizing suppressors of a secA2 mutant allele to better understand the mechanism of SecA2-dependent export. Intragenic suppressor mutations map to the surface of SecA2 and help identify functional regions of SecA2 that may promote interactions with SecYEG, SecA2 substrates or other partners of SecA2. Extragenic suppressor mutations map to a new component of the SecA2 pathway that we named SatS. In M. tuberculosis, SatS is required for the export of a subset of SecA2 substrates and for pathogenesis. SatS functions as a protein export chaperone that protects and promotes export of its specific substrates. Structural studies of SatS reveal a new fold combined with hydrophobic grooves representing potential sites of substrate binding. Taken together, the findings presented in this dissertation advance our understanding of the mechanism of the SecA2 export pathway and expand our appreciation of the diversity among chaperones by identifying SatS as a new type of protein export chaperone. Winter 2018 2018 Microbiology Molecular biology Genetics Chaperone, Mycobacterium tuberculosis, Protein Export eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Microbiology and Immunology Miriam Braunstein Thesis advisor Peggy Cotter Thesis advisor Virginia Miller Thesis advisor Jeff Dangl Thesis advisor Robert Nicholas Thesis advisor text Brittany Miller Creator Department of Microbiology and Immunology School of Medicine Identification of a Chaperone for the SecA2 Protein Export Pathway of Mycobacterium tuberculosis The bacterial pathogen Mycobacterium tuberculosis is responsible for the disease tuberculosis. To promote disease, M. tuberculosis exports proteins from the cytoplasm to the bacterial cell surface or out into the host environment. Exported proteins are in an ideal location to manipulate the host. All bacteria, including mycobacteria, utilize the Sec export system for the bulk of protein export. The Sec system is composed of an ATPase protein, SecA, and a membrane channel complex, SecYEG. Mycobacteria, along with some Gram-positive bacteria, contain a second, functionally distinct paralog of the SecA protein. In mycobacteria, the SecA responsible for housekeeping export is called SecA1 and is essential for bacterial survival, while the second SecA is called SecA2 and exports a smaller subset of proteins and is important for M. tuberculosis virulence. The mechanism of SecA2-dependent export is not well understood. Past data support a model where the mycobacterial SecA2 export pathway is integrated into the housekeeping Sec pathway, and SecA2 shares use of the same SecYEG channel as SecA1 to export its substrates. Like SecA1, SecA2 requires ATPase activity to function. In this dissertation, we take the approach of characterizing suppressors of a secA2 mutant allele to better understand the mechanism of SecA2-dependent export. Intragenic suppressor mutations map to the surface of SecA2 and help identify functional regions of SecA2 that may promote interactions with SecYEG, SecA2 substrates or other partners of SecA2. Extragenic suppressor mutations map to a new component of the SecA2 pathway that we named SatS. In M. tuberculosis, SatS is required for the export of a subset of SecA2 substrates and for pathogenesis. SatS functions as a protein export chaperone that protects and promotes export of its specific substrates. Structural studies of SatS reveal a new fold combined with hydrophobic grooves representing potential sites of substrate binding. Taken together, the findings presented in this dissertation advance our understanding of the mechanism of the SecA2 export pathway and expand our appreciation of the diversity among chaperones by identifying SatS as a new type of protein export chaperone. 2018 2018-12 Microbiology Molecular biology Genetics Chaperone; Mycobacterium tuberculosis; Protein Export eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Microbiology and Immunology Miriam Braunstein Thesis advisor Peggy Cotter Thesis advisor Virginia Miller Thesis advisor Jeff Dangl Thesis advisor Robert Nicholas Thesis advisor text Brittany Miller Creator Department of Microbiology and Immunology School of Medicine The bacterial pathogen Mycobacterium tuberculosis is responsible for the disease tuberculosis. To promote disease, M. tuberculosis exports proteins from the cytoplasm to the bacterial cell surface or out into the host environment. Exported proteins are in an ideal location to manipulate the host. All bacteria, including mycobacteria, utilize the Sec export system for the bulk of protein export. The Sec system is composed of an ATPase protein, SecA, and a membrane channel complex, SecYEG. Mycobacteria, along with some Gram-positive bacteria, contain a second, functionally distinct paralog of the SecA protein. In mycobacteria, the SecA responsible for housekeeping export is called SecA1 and is essential for bacterial survival, while the second SecA is called SecA2 and exports a smaller subset of proteins and is important for M. tuberculosis virulence. The mechanism of SecA2-dependent export is not well understood. Past data support a model where the mycobacterial SecA2 export pathway is integrated into the housekeeping Sec pathway, and SecA2 shares use of the same SecYEG channel as SecA1 to export its substrates. Like SecA1, SecA2 requires ATPase activity to function. In this dissertation, we take the approach of characterizing suppressors of a secA2 mutant allele to better understand the mechanism of SecA2-dependent export. Intragenic suppressor mutations map to the surface of SecA2 and help identify functional regions of SecA2 that may promote interactions with SecYEG, SecA2 substrates or other partners of SecA2. Extragenic suppressor mutations map to a new component of the SecA2 pathway that we named SatS. In M. tuberculosis, SatS is required for the export of a subset of SecA2 substrates and for pathogenesis. SatS functions as a protein export chaperone that protects and promotes export of its specific substrates. Structural studies of SatS reveal a new fold combined with hydrophobic grooves representing potential sites of substrate binding. Taken together, the findings presented in this dissertation advance our understanding of the mechanism of the SecA2 export pathway and expand our appreciation of the diversity among chaperones by identifying SatS as a new type of protein export chaperone. 2018 2018-12 Microbiology Molecular biology Genetics Chaperone; Mycobacterium tuberculosis; Protein Export eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Microbiology and Immunology Miriam Braunstein Thesis advisor Peggy Cotter Thesis advisor Virginia Miller Thesis advisor Jeff Dangl Thesis advisor Robert Nicholas Thesis advisor text Brittany Miller Creator Department of Microbiology and Immunology School of Medicine The bacterial pathogen Mycobacterium tuberculosis is responsible for the disease tuberculosis. To promote disease, M. tuberculosis exports proteins from the cytoplasm to the bacterial cell surface or out into the host environment. Exported proteins are in an ideal location to manipulate the host. All bacteria, including mycobacteria, utilize the Sec export system for the bulk of protein export. The Sec system is composed of an ATPase protein, SecA, and a membrane channel complex, SecYEG. Mycobacteria, along with some Gram-positive bacteria, contain a second, functionally distinct paralog of the SecA protein. In mycobacteria, the SecA responsible for housekeeping export is called SecA1 and is essential for bacterial survival, while the second SecA is called SecA2 and exports a smaller subset of proteins and is important for M. tuberculosis virulence. The mechanism of SecA2-dependent export is not well understood. Past data support a model where the mycobacterial SecA2 export pathway is integrated into the housekeeping Sec pathway, and SecA2 shares use of the same SecYEG channel as SecA1 to export its substrates. Like SecA1, SecA2 requires ATPase activity to function. In this dissertation, we take the approach of characterizing suppressors of a secA2 mutant allele to better understand the mechanism of SecA2-dependent export. Intragenic suppressor mutations map to the surface of SecA2 and help identify functional regions of SecA2 that may promote interactions with SecYEG, SecA2 substrates or other partners of SecA2. Extragenic suppressor mutations map to a new component of the SecA2 pathway that we named SatS. In M. tuberculosis, SatS is required for the export of a subset of SecA2 substrates and for pathogenesis. SatS functions as a protein export chaperone that protects and promotes export of its specific substrates. Structural studies of SatS reveal a new fold combined with hydrophobic grooves representing potential sites of substrate binding. Taken together, the findings presented in this dissertation advance our understanding of the mechanism of the SecA2 export pathway and expand our appreciation of the diversity among chaperones by identifying SatS as a new type of protein export chaperone. 2018 2018-12 Microbiology Molecular biology Genetics Chaperone; Mycobacterium tuberculosis; Protein Export eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Miriam Braunstein Thesis advisor Peggy Cotter Thesis advisor Virginia Miller Thesis advisor Jeff Dangl Thesis advisor Robert Nicholas Thesis advisor text Miller_unc_0153D_18243.pdf uuid:2ec7cb49-b745-46b8-9af5-83a69f15a812 2020-12-31T00:00:00 2018-11-29T18:31:48Z proquest application/pdf 5889571