Electrostatic Effects on the Structure of Intrinsically Disordered Proteins

Simple item page
dc.contributor.advisorWhitten, Steven T.
dc.contributor.authorEnglish, Lance R.
dc.contributor.committeeMemberKerwin, Sean M.
dc.contributor.committeeMemberLewis, Karen A.
dc.date.accessioned2016-11-09T16:40:43Z
dc.date.available2016-11-09T16:40:43Z
dc.date.issued2016-07
dc.description.abstractHighly flexible and dynamic proteins with negligible tertiary structure are known as intrinsically disordered proteins (IDPs). Current literature suggests the hydrodynamic dimensions of IDPs are dominated by electrostatic effects. However, other studies indicate polyproline II (PPII) content, a non-classical secondary structure, also greatly impacts the structure of IDPs. To test these suggestions in conjunction, we used the disordered N-terminal region (residues 1-93) of the human tumor suppressor protein p53 as our model and hydrodynamic radius (Rh) as a size reporter. We used size exclusion chromatography to measure the Rh and circular dichroism to measure PPII content at a pH range of 4.5-7.0. Previous research indicates proline and alanine as two of the residues with the highest PPII propensities. Hence, we repeated these measurements with two mutants: one in which all proline residues were replaced with glycines (Pro-) and one with all alanines replaced with glycines (Ala-). All three polypeptides have a net charge of -14.99 at pH 7.0 and should be significantly compacted at lower pHs due to a decrease in charge repulsion. As pH was decreased from 7.0 to 4.5, the Rh of the wildtype decreased by 15%, Ala- by 14%, and Pro- by 27%. These results show that prolines increase the spacing between charge groups, weakening electrostatic repulsion. Thus, charge effects are important to IDP structure, but are heavily modulated by PPII content.
dc.description.departmentChemistry and Biochemistry
dc.formatText
dc.format.extent104 pages
dc.format.medium1 file (.pdf)
dc.identifier.citationEnglish, L. R. (2016). <i>Electrostatic effects on the structure of intrinsically disordered proteins</i> (Unpublished thesis). Texas State University, San Marcos, Texas.
dc.identifier.urihttps://hdl.handle.net/10877/6350
dc.language.isoen
dc.subjectElectrostatic effects
dc.subjectHydrodynamic radius
dc.subjectIntrinsically disordered proteins
dc.subjectPolyproline II
dc.subjectSize exclusion chromotography
dc.subjectCircular dichroism
dc.subject.lcshProteins--Structureen_US
dc.subject.lcshProteins--Analysisen_US
dc.subject.lcshElectrostaticsen_US
dc.titleElectrostatic Effects on the Structure of Intrinsically Disordered Proteins
dc.typeThesis
thesis.degree.departmentChemistry and Biochemistry
thesis.degree.disciplineBiochemistry
thesis.degree.grantorTexas State University
thesis.degree.levelMasters
thesis.degree.nameMaster of Science

Files

Original bundle

Now showing 1 - 1 of 1
Thumbnail Image
Name:
ENGLISH-THESIS-2016.pdf
Size:
2.1 MB
Format:
Adobe Portable Document Format
Download

License bundle

Now showing 1 - 1 of 1
No Thumbnail Available
Name:
LICENSE.txt
Size:
2.12 KB
Format:
Plain Text
Description:
Download

Collections

Graduate Theses and Dissertations