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dc.contributor.advisor Matthews, Kathleen S.
dc.creatorChen, Jie
dc.date.accessioned 2009-06-04T08:33:26Z
dc.date.available 2009-06-04T08:33:26Z
dc.date.issued 1993
dc.identifier.urihttps://hdl.handle.net/1911/19122
dc.description.abstract The oligomeric assembly of the lactose repressor has been studied by a series of deletion and extension mutants at the C-terminal sequence. Deletion of the presumed mini leucine zipper sequence at the C-terminus (-5 aa, -11 aa, -18 aa, and -32 aa) has resulted in a family of dimeric repressors, while deletion of the last four amino acids (-4 aa) does not affect the oligomeric state or function of the repressor. Furthermore, extension of the C-terminus with leucine zipper-forming sequences (G359V+5 and GCN/C) has been deduced to strengthen a subunit interaction in tetramers. The role of the presumed mini leucine zipper in tetramer formation for the lac repressor is therefore confirmed. In addition, a long-axis dimer (GCN/C-Y282D) is obtained from increasing the leucine zipper length and disrupting a presumably distinctive interface composed of Tyr$\sp{282}$ and Lys$\sp{84}$. The generation of this altered protein confirms the postulate that there are two distinctive subunit interfaces for the assembly of tetrameric repressor. Detailed characterization of these mutant repressors has provided insight into the relationship between structure and function in the lac repressor. The subunit communication upon inducer-binding in a tetrameric repressor is between the two side-by-side monomers and does not appear to involve monomers in end-to-end orientation. The lower operator-affinity observed for the deletion dimers compared to the tetramer is derived from a difference in the association process.
dc.format.extent 257 p.
dc.format.mimetype application/pdf
dc.language.iso eng
dc.subjectMolecular biology
Genetics
dc.title Genetic and physical studies of quaternary structure of lactose repressor
dc.type.genre Thesis
dc.type.material Text
thesis.degree.department Biology
thesis.degree.discipline Natural Sciences
thesis.degree.grantor Rice University
thesis.degree.level Doctoral
thesis.degree.name Doctor of Philosophy
dc.identifier.citation Chen, Jie. "Genetic and physical studies of quaternary structure of lactose repressor." (1993) Diss., Rice University. https://hdl.handle.net/1911/19122.


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