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postgraduate thesis: Structural studies of two nucleoid-associated proteins : histone-like nucleoid-structuring protein H-NS and α-hemolysin expression-modulating protein Hha

TitleStructural studies of two nucleoid-associated proteins : histone-like nucleoid-structuring protein H-NS and α-hemolysin expression-modulating protein Hha
Authors
Issue Date2014
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
Citation
Cao, W. [曹威]. (2014). Structural studies of two nucleoid-associated proteins : histone-like nucleoid-structuring protein H-NS and α-hemolysin expression-modulating protein Hha. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5194724
AbstractIn prokaryotic cells, the nucleoid contains almost all the genetic materials as well as a number of nucleoid structuring factors. The nucleoid-associated proteins (NAPs) are known to have low molecular weight and the ability to form dimer or oligomer, and most of them can bind to DNA for regulation of gene expression. The Histone-like nucleoid structuring protein H-NS, well studied as one of the NAPs, acts as a global transcriptional repressor. It has independent functional N-terminal domain for oligomerization and C-terminal domain for DNA binding, joined by a flexible linker. H-NS contributes to horizontal genes transfer and responses to environmental factors like temperature or pH, which would influence the oligomerization ability of H-NS and DNA binding. The α-hemolysin expression-modulating protein Hha is a member of the Hha-YmoA family, expressed only in Gram-negative Enterobacteriaceae as a modulator of virulence factors expression. In E. coli, the binding of Hha to H-NS can modulate the expression of α-hemolysin operon, which is essential for the H-NS-regulated gene expression. In this study, both Hha and the oligomerization domain of H-NS (H-NS64) were expressed in E. coli and the purified proteins were crystallized. The Hha crystals diffracted to 2.2 Å; and the HhA/H-NS complex crystals diffracted to 1.8 Å. Both structures were successfully determined by molecular replacement method. Comparisons were carried out between the published apo Hha and H-NS structures and our complex structures. The structures showed the binding details between H-NS and Hha and also conformational changes of each protein, which may indicate how Hha regulates gene expressions through H-NS.
DegreeMaster of Philosophy
SubjectProteins - Structure
Dept/ProgramPhysiology
Persistent Identifierhttp://hdl.handle.net/10722/208420

 

DC FieldValueLanguage
dc.contributor.authorCao, Wei-
dc.contributor.author曹威-
dc.date.accessioned2015-03-04T09:12:56Z-
dc.date.available2015-03-04T09:12:56Z-
dc.date.issued2014-
dc.identifier.citationCao, W. [曹威]. (2014). Structural studies of two nucleoid-associated proteins : histone-like nucleoid-structuring protein H-NS and α-hemolysin expression-modulating protein Hha. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5194724-
dc.identifier.urihttp://hdl.handle.net/10722/208420-
dc.description.abstractIn prokaryotic cells, the nucleoid contains almost all the genetic materials as well as a number of nucleoid structuring factors. The nucleoid-associated proteins (NAPs) are known to have low molecular weight and the ability to form dimer or oligomer, and most of them can bind to DNA for regulation of gene expression. The Histone-like nucleoid structuring protein H-NS, well studied as one of the NAPs, acts as a global transcriptional repressor. It has independent functional N-terminal domain for oligomerization and C-terminal domain for DNA binding, joined by a flexible linker. H-NS contributes to horizontal genes transfer and responses to environmental factors like temperature or pH, which would influence the oligomerization ability of H-NS and DNA binding. The α-hemolysin expression-modulating protein Hha is a member of the Hha-YmoA family, expressed only in Gram-negative Enterobacteriaceae as a modulator of virulence factors expression. In E. coli, the binding of Hha to H-NS can modulate the expression of α-hemolysin operon, which is essential for the H-NS-regulated gene expression. In this study, both Hha and the oligomerization domain of H-NS (H-NS64) were expressed in E. coli and the purified proteins were crystallized. The Hha crystals diffracted to 2.2 Å; and the HhA/H-NS complex crystals diffracted to 1.8 Å. Both structures were successfully determined by molecular replacement method. Comparisons were carried out between the published apo Hha and H-NS structures and our complex structures. The structures showed the binding details between H-NS and Hha and also conformational changes of each protein, which may indicate how Hha regulates gene expressions through H-NS.-
dc.languageeng-
dc.publisherThe University of Hong Kong (Pokfulam, Hong Kong)-
dc.relation.ispartofHKU Theses Online (HKUTO)-
dc.rightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works.-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.subject.lcshProteins - Structure-
dc.titleStructural studies of two nucleoid-associated proteins : histone-like nucleoid-structuring protein H-NS and α-hemolysin expression-modulating protein Hha-
dc.typePG_Thesis-
dc.identifier.hkulb5194724-
dc.description.thesisnameMaster of Philosophy-
dc.description.thesislevelMaster-
dc.description.thesisdisciplinePhysiology-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.5353/th_b5194724-

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