Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 143-164). Also available on the Internet.

by Chung Wilson. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 126-149). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract (English) --- p.ii / Abstract (Chinese) --- p.v / Content --- p.vii / Abbreviations --- p.xii / List of Figures --- p.xv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Alzheimer's disease --- p.1 / Chapter 1.1.1 --- History of Alzheimer's disease --- p.1 / Chapter 1.1.2 --- Definition of Alzheimer's disease --- p.2 / Chapter 1.1.3 --- Symptoms of Alzheimer's disease --- p.6 / Chapter 1.1.3.1 --- Memory deficit --- p.6 / Chapter 1.1.3.2 --- Difficulty in learning --- p.6 / Chapter 1.1.3.3 --- Language difficulties --- p.7 / Chapter 1.1.3.4 --- Decline in ability to perform routine tasks --- p.7 / Chapter 1.1.4 --- Prevalence of Alzheimer's disease --- p.8 / Chapter 1.2 --- Present treatment of Alzheimer's disease --- p.9 / Chapter 1.2.1 --- Acetylcholine and dementia --- p.9 / Chapter 1.2.2 --- Tacrine as first drug approved by US Food and Drug Administration --- p.9 / Chapter 1.3 --- Proposed theory of Alzheimer's disease formation --- p.10 / Chapter 1.3.1 --- The amyloid cascade hypothesis --- p.10 / Chapter 1.3.1.1 --- The amyloid precursor protein --- p.10 / Chapter 1.3.1.2 --- The processing of amyloid precursor protein --- p.12 / Chapter 1.3.1.3 --- Neurotoxic effect of amyloid plaque --- p.15 / Chapter 1.3.1.4 --- Genetic factors --- p.15 / Chapter 1.3.1.4.1 --- The amyloid precursor protein --- p.15 / Chapter 1.3.1.4.2 --- Apolipoprotein E (ApoE) --- p.16 / Chapter 1.3.1.4.3 --- Presenilin genes --- p.17 / Chapter 1.3.2 --- Tau and tangle hypothesis --- p.19 / Chapter 1.3.2.1 --- Tau protein --- p.19 / Chapter 1.3.2.2 --- Paired helical filaments (PHF) --- p.20 / Chapter 1.3.2.3 --- Tau protein kinase --- p.20 / Chapter 1.3.2.3.1 --- Glycogen synthase kinase-3 (GSK-3) --- p.21 / Chapter 1.3.2.3.2 --- Cyclin-dependent kinase 5 (CDK5) --- p.21 / Chapter 1.3.2.4 --- Tangle leads to dementia --- p.22 / Chapter 1.4 --- Cross-talk between the two hypotheses --- p.24 / Chapter 1.5 --- β -secretase (BACE) --- p.24 / Chapter 1.5.1 --- Discovery of β-secretase (BACE) --- p.24 / Chapter 1.5.2 --- Detailed structure of BACE --- p.25 / Chapter 1.5.3 --- Comparsion of human and mouse BACE --- p.27 / Chapter 1.5.4 --- Comparsion of BACE-1 with BACE-2 --- p.27 / Chapter 1.5.5 --- Properties of BACE-1 --- p.28 / Chapter 1.5.6 --- Expression of BACE in E.coli --- p.29 / Chapter 1.5.7 --- Expression of BACE in mammalian cells --- p.30 / Chapter 1.6 --- Objectives of the present study --- p.32 / Chapter Chapter 2 --- Materials and Methods --- p.34 / Chapter 2.1 --- Recombinant DNA techniques --- p.34 / Chapter 2.1.1 --- Amplification of genes by PCR techniques --- p.34 / Chapter 2.1.2 --- Agarose gel electrophoresis --- p.34 / Chapter 2.1.3 --- Extraction of DNA from agarose gel --- p.35 / Chapter 2.1.4 --- Digestion of various vectors and inserts --- p.36 / Chapter 2.1.5 --- Ligation of DNA fragments --- p.36 / Chapter 2.1.6 --- Preparation of Escherichia coli competent cells --- p.37 / Chapter 2.1.7 --- Bacterial transformation --- p.38 / Chapter 2.1.8 --- Minipreparation of plasmid DNA --- p.38 / Chapter 2.1.9 --- Large scale preparation of plasmid DNA --- p.39 / Chapter 2.1.10 --- Strain storage and revival --- p.40 / Chapter 2.1.11 --- Plasma DNA purification by High Pure plasmid isolation kit --- p.41 / Chapter 2.1.12 --- DNA sequencing --- p.42 / Chapter 2.1.13 --- Quantitation of DNA by spectrophotometric method --- p.43 / Chapter 2.2 --- Prokaryotic protein expression --- p.43 / Chapter 2.2.1 --- Selection of appropriate clones for recombinant protein expression using conventional method --- p.43 / Chapter 2.2.2 --- Selection of appropriate clones for recombinant protein expression using modified method --- p.44 / Chapter 2.2.3 --- Large -scale expression of recombinant human BACE protein using modified method --- p.45 / Chapter 2.2.4 --- Preparation of inclusion body from the bacterial expression culture --- p.46 / Chapter 2.2.5 --- Refolding of human BACE --- p.47 / Chapter 2.2.6 --- Purification of recombinant human BACE by immobilized metal ion affinity chromatography (IMAC) --- p.47 / Chapter 2.2.7 --- Protein concentration determination --- p.48 / Chapter 2.2.8 --- Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) --- p.48 / Chapter 2.2.9 --- Western blotting --- p.50 / Chapter 2.2.10 --- Plasmid stability test --- p.50 / Chapter 2.3 --- Mammalian cell expression --- p.51 / Chapter 2.3.1 --- Transient transfection --- p.51 / Chapter 2.3.2 --- Measuring transfection efficiency --- p.52 / Chapter 2.3.3 --- Stable transfection --- p.52 / Chapter 2.3.4 --- Preparation of membrane extracts from CHO cells --- p.53 / Chapter 2.4 --- HPLC analysis --- p.53 / Chapter 2.4.1 --- Preparation of samples --- p.53 / Chapter 2.4.2 --- Reverse phase HPLC --- p.54 / Chapter 2.5 --- Fluorometric assay --- p.54 / Chapter 2.6 --- Immunohistochemistry --- p.55 / Chapter 2.7 --- Reagents and buffers --- p.55 / Chapter 2.7.1 --- Medium for bacterial culture --- p.56 / Chapter 2.7.2 --- Reagents for preparation of plasmid DNA --- p.56 / Chapter 2.7.3 --- Buffers for agarose gel electrophoresis --- p.57 / Chapter 2.7.4 --- Buffers for SDS-PAGE --- p.58 / Chapter 2.7.5 --- Buffer for purification of protein --- p.60 / Chapter 2.7.6 --- Buffer for Western Blotting --- p.61 / Chapter 2.7.7 --- Culturing medium of CHO cells --- p.62 / Chapter 2.7.8 --- Solutions for estimating transfection efficiency --- p.63 / Chapter 2.7.9 --- Reagents for HPLC --- p.64 / Chapter 2.7.10 --- Reagents for fluorometric assays --- p.65 / Chapter 2.7.11 --- Reagents for Immunohistochemistry --- p.66 / Chapter Chapter 3 --- Results --- p.67 / Chapter 3.1 --- Expression of BACE in E. coli --- p.67 / Chapter 3.1.1 --- Cloning of truncated human and mouse BACE into pRSET --- p.67 / Chapter 3.1.2 --- Expression of BACE in BL21(DE3)LysS cells --- p.70 / Chapter 3.1.2.1 --- Expression of truncated mouse and human BACEin BL21(DE3)LysS cells using conventional method --- p.70 / Chapter 3.1.2.2 --- Expression of truncated mouse and human BACEin BL21(DE3)LysS cells using modified method --- p.72 / Chapter 3.1.3 --- Analysis of BACE activity of purified recombinant proteins --- p.76 / Chapter 3.1.3.1 --- Fluorometric analysis --- p.76 / Chapter 3.2 --- Expression of BACE in mammalian cells --- p.81 / Chapter 3.2.1 --- "Cloning of full length mouse and human BACE into pCDNA3, pCDNA4HisMax" --- p.81 / Chapter 3.2.2 --- Transient transfection --- p.84 / Chapter 3.2.2.1 --- Western blot analysis --- p.86 / Chapter 3.2.2.2 --- Fluorometric analysis --- p.88 / Chapter 3.2.2.3 --- HPLC --- p.91 / Chapter 3.2.3 --- Stable transfection --- p.100 / Chapter 3.2.3.1 --- Western blot analysis --- p.101 / Chapter 3.2.3.2 --- Fluorometric analysis --- p.103 / Chapter 3.2.3.3 --- HPLC --- p.105 / Chapter 3.2.3.4 --- Immunohistochemistry --- p.112 / Chapter Chapter 4 --- Discussion --- p.115 / References --- p.126 / Appendix --- p.i / Chapter A1 --- Vector circle map --- p.i / Chapter A1-1 --- Vector circle map of pBluescript II- --- p.i / Chapter A1-2 --- Vector circle map of pCDNA3 --- p.ii / Chapter A1-3 --- Vector circle map of pCDNA4HisMax --- p.iii / Chapter A1-4 --- Vector circle map of pRSET --- p.iv / Chapter A2 --- Primer lists --- p.v / Chapter A3 --- Chemical structure of fluorophore and quench used in fluorometric assay --- p.vi

Variable-temperature Fourier transform infrared (VT-FTIR) spectroscopy in conjunction with 2D correlation analysis was employed to study the unfolding of aspartate transcarbamylase (ATCase) and its individual subunits. The regulatory subunit (RSU) was uniformly labeled with 13C/15N and then reconstituted with the unlabeled catalytic subunit (CSU) to form the holoenzyme. The activity of the holoenzyme was shown to be unaffected by the isotopic labeling of the RSU. The VT-FTIR investigation of the isolated CSU and the CSU in the holoenzyme revealed that the CSU is more thermally stable when bound to the RSU (i.e., in the holoenzyme). The RSU also showed more thermal stability when bound to the CSU. The sequences of events leading to the unfolding of the isolated CSU and RSU and the CSU in the holoenzyme were deduced by 2D correlation analysis of the VT-FTIR spectra. The results for the isolated CSU demonstrated that beta-sheets unfold first, followed by a-helices and then turns, and finally aggregates form. The sequence of unfolding of the RSU showed an increase of turns followed by a loss of intramolecular beta sheets, then a loss of alpha-helices and the formation of aggregates. The CSU in the holoenzyme exhibited a slightly different unfolding pathway and was observed to unfold subsequent to the unfolding of the RSU, consistent with the two thermal transitions observed by differential scanning calorimetry.

This thesis is an investigation of the role of the prosegment (PS) of pepsinogen in the binding, refolding and inhibition of pepsin. Native pepsin (Np) is irreversibly denatured, and folds to a stable, non-native state under refolding conditions, termed refolded pepsin (Rp) (Dee and Yada 2010). When added separately, the PS binds Rp, catalyzes folding to the native-like state and inhibits Np (Dee and Yada 2010). It was hypothesized, owing to the high sequence conservation, that N-terminal PS residues are critical to PS catalyzed folding. Synthetic peptides of N-terminal truncations (N16, N29), C-terminal truncations (C15, C28), and full length, wild-type (Wt) PS were examined. N-terminal residues were required for binding to Rp and catalyzing folding, while both N29 and C28 truncations had similar inhibition constants. Remarkably, the foldase activity of N-terminal truncation (N29) was only 2.5 fold slower than Wt, supporting that PS foldase activity is stored almost entirely within the highly conserved N29 region.

Fourier transform infrared (FTIR) spectroscopy is a powerful tool for probing protein structure-function relationships. With the use of isotope editing, it can also be employed to elucidate protein-nucleic acid interactions. This technique was used to study the sequence of heat-induced unfolding of the uniformly labeled 13C regulatory subunit (RSU) of E. coli aspartate transcarbamylase (ATCase) with its inhibitor CTP. The absorption of CTP in the amide I' region limits our ability to detect protein conformational changes upon binding of CTP. Therefore, by labeling the protein with 13C shifts the amide I' band ~ 40 cm -1 and clearly separates the protein bands from those of CTP. Variable-temperature (VT) FTIR spectroscopy was then employed to monitor the thermal unfolding of the labeled RSU in the presence and absence of CTP. / In addition, isotope editing was further explored to probe domain-domain interactions of the two domains of RSU using intein technology. Intein technology provides a novel means by which isotope editing can be performed to extract information on protein inter-domain and inter-subunit interactions by spectroscopic analysis but has not yet been exploited in Fourier transform infrared (FTIR) spectroscopy. The objective of this project is to present for the first time the feasibility of segmental labeling through intein-mediated protein ligation (IPL) for the purpose of studying conformational changes by FTIR spectroscopy, using ATCase as a model enzyme. In the first phase of this project, the RSU of ATCase, which houses a Zn-binding domain and a nucleotide binding domain, was reconstructed from its isolated domains using commercially available intein-base expression vectors. As steps towards obtaining an isotope labeled RSU, we have fused each domain to separate inteins. Following affinity purification, the intein tags were chemically cleaved and the reactive ends of the two RSU domains were ligated together to form a peptide. Although ligation was successful, improved yields are required for the FTIR spectroscopic studies.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 4 uppsatser.

Title from PDF of title page (University of Missouri--Columbia, viewed on February 23, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Jonathan A. Green. Vita Includes bibliographical references.

Thesis (Ph.D.)--McMaster University, 2003. / Advisor: Gerard Wright. Includes bibliographical references. Also available via World Wide Web.

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