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Dissertation/Thesis Abstract

Truncation analysis of apolipophorin III, a five helix bundle
by Dwivedi, Pankaj, M.S., California State University, Long Beach, 2012, 73; 1521618
Abstract (Summary)

Apolipophorin Ill (apoLp-lll) from the insect Locusta migratoria is a model apolipoprotein to study their structure-function relationship. In contrast to the common four-helix bundle motif, apoLp-III is a bundle of five amphipathic α-helices (H1-H5). It was hypothesized that H1-H5 of apoLp-III may have evolved to modulate lipid binding. To verify this, N-terminal (H2-H5) and C-terminal (H1-H4) helix deletion mutants were designed. H2-H5 was expressed in a bacterial expression system. Since H1-H4 could not be expressed, a methionine mutant was designed allowing removal of helix 5 by CNBr digestion. Five additional truncation mutants apoLp-III (1-135, 1-139, 1-143, 1-149 and 1-153) were designed by stop codon insertion to determine the region in helix 5 required for protein expression. Circular dichroism and guanidine-HCl denaturation analysis showed a significantly lower α-helical content and stability for all mutants compared to wild type apoLp-III. However, a substantially higher lipid binding was observed for all mutant proteins.

Indexing (document details)
Advisor: Weers, Paul M. M.
Commitee: McAbee, Douglas D., Narayanaswami, Vasanthy, Weers, Paul M. M.
School: California State University, Long Beach
Department: Chemistry and Biochemistry
School Location: United States -- California
Source: MAI 51/04M(E), Masters Abstracts International
Subjects: Biochemistry
Publication Number: 1521618
ISBN: 978-1-267-79047-7
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