Graduation date: 1994

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 83-91). Also available on the World Wide Web.

Vaccinia virus (VV) is a large double-stranded DNA virus that is a prototypic member of the orthopoxvirus family. Previous works has showed that three of the major structural proteins found within the mature VV virion core 4a, 4b, and 25K are produced from higher molecular weight precursors at late times during infection and processed via a common morphogenic cleavage pathway that is intimately linked with virion assembly and maturation. The enzyme that carries out these cleavage reactions is unknown. A transient expression assay was used to demonstrate that the 17L gene product and its encoded cysteine proteinase activity is responsible for cleavage of each of the three major core protein precursors. Cleavage was demonstrated to occur at the authentic Ala-Gly-Xaa cleavage sites and require active enzyme. A truncated 17L protein lost the ability to cleave the core protein precursors. A conditional-lethal recombinant virus was constructed in which the expression of the 17L gene is under the control of the tetracycline operator/repressor system. In the absence of 17L expression, processing of the major VV core proteins is inhibited and electron microscopy revealed defects in virion morphogenesis prior to complete core condensation. Plasmid-borne 17L is capable of rescuing the growth of this virus. A structural model of 17L was developed and a unique chemical library was assayed for both cell toxicity and the ability to inhibit the growth of VV in tissue culture cells. A novel class of inhibitors was discovered that is capable of inhibiting VV. An in-vitro cleavage assay was developed to further characterize the activity of 17L. This assay is based on producing the major core protein precursors in a coupled transcription and translation assay and then mixing them with 17L enzyme extracts. Using this assay, 17L is shown to be capable of cleavage of each substrate. 17L is further characterized as a cysteine proteinase due to the inhibitory effects of known cysteine proteinase inhibitors such as NEM and iodoacetic acid, as well as through the use of specific small molecule inhibitors in this in-vitro assay. / Graduation date: 2005

More than half of the recognized genera of positive strand RNA viruses employ polyprotein processing as one of the strategies for their genome expression. Normally, this processing is mediated by virus-encoded proteinases that belong to the trypsin-like or papain-like family. In particular, papain-like, leader proteinases were found in diverse families of human, animal, plant, and fungal positive strand RNA viruses. In addition to autocatalytic processing, these proteinases play a variety of roles in the virus life cycle. In plant potyviruses, a papain-like helper component-proteinase (HC-Pro) was implicated in genome amplification, cell-to-cell movement, long distance transport, and suppression of host defense. The p29 proteinase encoded by a fungal hypovirus CHV1 was found to be dispensable for virus replication, but it was identified as a major determinant of viral pathogenicity. In an animal equine aterivirus (EAV), a papain-like proteinase nspl was demonstrated to possess a putative zinc finger domain, which functions in subgenomic RNA synthesis, although it is not essential for virus replication. The Lab proteinase of the foot and mouse disease virus (FMDV) is involved in inhibition of cellular mRNA translation and in virus spread in infected animals. In general, it appears that functional plasticity of the papain-like leader proteinases played an important role in the evolution of viral diversity. Here, we examined the functions of a papain-like leader proteinase (L-Pro) in the life cycle of the beet yellows closterovirus (BYV). It was found that L-Pro is required for autoproteolytic processing, genome amplification, virus invasiveness and cell-to-cell movement for BYV. The gene swapping experiments involving several closterviruses, a potyvirus, as well as CHV1, FMDV, and EAV revealed complex functional profiles of the papain-like leader proteinases. The possible mechanisms that underlie L-Pro functions are discussed. / Graduation date: 2002

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 61-74). Also available on the World Wide Web.

Chu Ling Hon Matthew. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 201-223). / Abstracts in English and Chinese. / Declaration --- p.i / Thesis/Assessment Committee --- p.ii / Abstract --- p.iii / 摘要 --- p.vi / Acknowledgements --- p.viii / General abbreviations --- p.xi / Abbreviations of chemicals --- p.xv / Table of Contents --- p.xvi / List of Figures --- p.xxiii / List of tables --- p.xxviii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Severe Acute Respiratory Syndrome (SARS) - Three Years in Review --- p.1 / Chapter 1.1.1 --- Epidemiology --- p.1 / Chapter 1.1.2 --- Clinical presentation --- p.3 / Chapter 1.1.3 --- Diagnostic tests --- p.5 / Chapter 1.2 --- Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) --- p.7 / Chapter 1.2.1 --- SARS - Identification of the etiological agent --- p.7 / Chapter 1.2.2 --- The coronaviruses --- p.9 / Chapter 1.2.3 --- The genome organization of SARS-CoV --- p.11 / Chapter 1.2.4 --- The life cycle of SARS-CoV --- p.13 / Chapter 1.3 --- Spike Glycoprotein (S protein) of SARS-CoV --- p.15 / Chapter 1.3.1 --- SARS-CoV S protein --- p.15 / Chapter 1.3.2 --- S protein-driven infection --- p.17 / Chapter 1.4 --- SARS-CoV S Protein Fusion Core --- p.22 / Chapter 1.4.1 --- Heptad repeat and coiled coil --- p.22 / Chapter 1.4.2 --- The six-helix coiled coil bundle structure --- p.25 / Chapter 1.5 --- 3C-like Protease (3CLpro) of SARS-CoV --- p.28 / Chapter 1.5.1 --- Extensive proteolytic processing of replicase polyproteins --- p.28 / Chapter 1.5.2 --- SARS-CoV 3CLpro --- p.30 / Chapter 1.5.3 --- Substrate Specificity of SARS-CoV 3CLpro --- p.31 / Chapter 1.6 --- SARS Drug Development --- p.32 / Chapter 1.6.1 --- Drug targets of SARS-CoV --- p.32 / Chapter 1.6.2 --- Current anti-SARS drugs --- p.36 / Chapter 1.7 --- Project Objectives --- p.39 / Chapter 1.7.1 --- Characterization of SARS-CoV S protein fusion core --- p.39 / Chapter 1.7.2 --- Characterization of SARS-CoV 3CLpr0 substrate specificity --- p.40 / Chapter 2 --- Materials and Methods --- p.42 / Chapter 2.1 --- Characterization of SARS-CoV S Protein Fusion Core --- p.42 / Chapter 2.1.1 --- Bioinformatics analyses of heptad repeat regions of SARS- CoV S protein --- p.42 / Chapter 2.1.2 --- Recombinant protein approach --- p.43 / Chapter 2.1.2.1 --- Plasmids construction --- p.43 / Chapter 2.1.2.2 --- Protein expression and purification --- p.52 / Chapter 2.1.2.3 --- Amino acid analysis --- p.57 / Chapter 2.1.2.4 --- GST-pulldown experiment --- p.58 / Chapter 2.1.2.5 --- Laser light scattering --- p.61 / Chapter 2.1.2.6 --- Size-exclusion chromatography --- p.62 / Chapter 2.1.2.7 --- Circular dichroism spectroscopy --- p.62 / Chapter 2.1.3 --- Synthetic peptide approach --- p.64 / Chapter 2.1.3.1 --- Peptide synthesis --- p.64 / Chapter 2.1.3.2 --- Native polyacrylamide gel electrophoresis --- p.65 / Chapter 2.1.3.3 --- Size-exclusion high-performance liquid chromato-graphy --- p.66 / Chapter 2.1.3.4 --- Laser light scattering --- p.66 / Chapter 2.1.3.5 --- Circular dichroism spectroscopy --- p.67 / Chapter 2.2 --- Identification of SARS-CoV Entry Inhibitors --- p.70 / Chapter 2.2.1 --- HIV-luc/SARS pseudotyped virus entry inhibition assay --- p.70 / Chapter 2.2.2 --- Recombinant protein- and synthetic peptide-based biophysical assays --- p.74 / Chapter 2.2.3 --- Molecular modeling --- p.75 / Chapter 2.3 --- Characterization of SARS-CoV 3CLpro Substrate Specificity --- p.79 / Chapter 2.3.1 --- Protein expression and purification --- p.79 / Chapter 2.3.2 --- """Cartridge replacement"" solid-phase peptide synthesis" --- p.80 / Chapter 2.3.3 --- Peptide cleavage assay and mass spectrometric analysis --- p.83 / Chapter 3 --- Results --- p.84 / Chapter 3.1 --- Characterization of SARS-CoV S Protein Fusion Core --- p.84 / Chapter 3.1.1 --- Bioinformatics analyses of heptad repeat regions of SARS- CoV S protein --- p.84 / Chapter 3.1.2 --- Recombinant protein approach --- p.87 / Chapter 3.1.2.1 --- "Plasmids construction of pET-28a-His6-HRl, pGEX-6P-l-HR2 and pGEX-6P-l-2-Helix" --- p.87 / Chapter 3.1.2.2 --- Protein expression and purification --- p.92 / Chapter 3.1.2.3 --- GST-pulldown experiment --- p.101 / Chapter 3.1.2.4 --- Laser light scattering --- p.103 / Chapter 3.1.2.5 --- Size-exclusion chromatography --- p.105 / Chapter 3.1.2.6 --- Circular dichroism spectroscopy --- p.107 / Chapter 3.1.3 --- Synthetic peptide approach --- p.112 / Chapter 3.1.3.1 --- Peptide synthesis --- p.112 / Chapter 3.1.3.2 --- Native polyacrylamide gel electrophoresis --- p.116 / Chapter 3.1.3.3 --- Size-exclusion high-performance liquid chromatography --- p.117 / Chapter 3.1.3.4 --- Laser light scattering --- p.122 / Chapter 3.1.3.5 --- Circular dichroism spectroscopy --- p.124 / Chapter 3.2 --- Identification of SARS-CoV Entry Inhibitors --- p.129 / Chapter 3.2.1 --- HIV-luc/SARS pseudotyped virus entry inhibition assay --- p.129 / Chapter 3.2.2 --- Recombinant protein- and synthetic peptide-based biophysical assays --- p.131 / Chapter 3.2.3 --- Molecular modeling --- p.135 / Chapter 3.3 --- Characterization of SARS-CoV 3CLpro Substrate Specificity --- p.141 / Chapter 3.3.1 --- Protein expression and purification --- p.141 / Chapter 3.3.2 --- Substrate specificity preference of SARS-CoV 3CLpr0 --- p.142 / Chapter 3.3.3 --- "Primary and secondary screening using the ""cartridge replacement strategy""" --- p.142 / Chapter 4 --- Discussion --- p.149 / Chapter 4.1 --- Characterization of SARS-CoV S Protein Fusion Core --- p.149 / Chapter 4.1.1 --- Design of recombinant proteins and synthetic peptides of HR regions --- p.149 / Chapter 4.1.2 --- Recombinant protein approach --- p.151 / Chapter 4.1.3 --- Synthetic peptide approach --- p.153 / Chapter 4.1.4 --- Summary of the present and previous studies in the SARS-CoV S protein fusion core --- p.157 / Chapter 4.2 --- Identification of SARS-CoV Entry Inhibitors --- p.167 / Chapter 4.2.1 --- HIV-luc/SARS pseudotyped virus entry inhibition assay --- p.167 / Chapter 4.2.2 --- Identification of peptide inhibitors --- p.168 / Chapter 4.2.3 --- Identification of small molecule inhibitors --- p.172 / Chapter 4.3 --- Characterization of SARS-CoV 3CLpro Substrate Specificity --- p.183 / Chapter 4.3.1 --- A comprehensive overview of the substrate specificity of SARS-CoV 3CLpro --- p.184 / Chapter 4.3.2 --- The development of the rapid and high-throughput screening strategy for protease substrate specificity --- p.188 / Appendix --- p.191 / Chapter I. --- Nucleotide Sequence of S protein of SARS-CoV --- p.191 / Chapter II. --- Protein Sequence of S protein of SARS-CoV --- p.194 / Chapter III. --- Protein Sequence of 3CLpro of SARS-CoV --- p.195 / Chapter IV. --- Vector maps --- p.196 / Chapter 1. --- Vector map and MCS of pET-28a --- p.196 / Chapter 2. --- Vector map and MCS of pGEX-6P-l --- p.197 / Chapter V. --- Electrophoresis markers --- p.198 / Chapter 1. --- GeneRuler´ёØ 1 kb DNA Ladder --- p.198 / Chapter 2. --- GeneRuler´ёØ 100bp DNA Ladder --- p.198 / Chapter 3. --- High-range Rainbow Molecular Weight Markers --- p.199 / Chapter 4. --- Low-range Rainbow Molecular Weight Markers --- p.199 / Chapter VI. --- SDS-PAGE gel preparation protocol --- p.200 / References --- p.201

Chong Lin-Tat. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 76-78). / Abstracts in English and Chinese. / Chapter Chapter 1 --- introduction / Chapter 1.1 --- Severe acute respiratory syndrome Coronavirus (SARS CoV) --- p.13 / Figure 1.1 Genome organization and putative functional ORFs of SARS CoV --- p.14 / Chapter 1.2 --- SARS main protease / Chapter 1.2.1 --- Three dimensional structure --- p.15 / Figure 1.2 Ribbon illustration of the SARS-coronavirus main protease --- p.17 / Figure 1.3 Surface representations of P1 and P2 substrate-binding pocket of main protease --- p.18 / Chapter 1.2.2 --- Substrate specificities --- p.19 / Table 1.1. Eleven predicted cleavage sites of SARS CoV main protease --- p.21 / Chapter 1.3 --- Protein-based FRET assay system --- p.22 / Figure 1.4. The principle of fluorescent resonance energy transfer (FRET) --- p.24 / Chapter 1.4 --- Objectives --- p.25 / Chapter Chapter 2 --- Materials and Methods / Chapter 2.1 --- General Techniques / Chapter 2.1.1 --- Preparation and transformation of competent E. coli DH5a and23 BL21 (DE3)pLysS --- p.26 / Chapter 2.1.2 --- Minipreparation of plasmid DNA (Invitrogen) --- p.27 / Chapter 2.1.3 --- Spectrophotometric quantitation DNA --- p.28 / Chapter 2.1.4 --- Agarose gel electrophoresis / Chapter 2.1.5 --- Purification of DNA from agarose gel (Invitrogen) / Chapter 2.1.6 --- Restriction digestion of DNA fragments --- p.29 / Chapter 2.1.7 --- Ligation of DNA fragments into vector / Table 2.1. Standard recipe of ligation reaction --- p.30 / Chapter 2.1.8 --- SDS-PAGE electrophoresis --- p.31 / Table 2.2. Standard recipe of separating gel for SDS-PAGE --- p.32 / Table 2.3. Standard recipe of stacking gel for SDS-PAGE --- p.33 / Chapter 2.2 --- Sub-cloning and site-directed mutagenesis / Chapter 2.2.1 --- Sub-cloning of SARS Co V main protease --- p.34 / Chapter 2.2.2 --- Sub-cloning of Substrate / Chapter 2.2.3 --- Site-directed mutagenesis of substrate variant --- p.35 / Table 2.4 Primer sequence for generating substrate variants --- p.36 / Table 2.5. Standard recipe of Polymerase Chain Reaction (PCR) --- p.40 / Table 2.6. Polymerase Chain Reaction (PCR) profile --- p.41 / Chapter 2.3 --- Sample preparation / Chapter 2.3.1 --- Expression of recombinant proteins --- p.42 / SARS CoV main protease / Substrate and substrate variants / Chapter 2.3.2 --- Purification of recombinant proteins / SARS CoV main protease / Substrate and substrate variants / Chapter 2.4 --- Protein-based FRET kinetic analysis --- p.45 / Chapter 2.5 --- A model for substrate-enzyme binding by docking simulation --- p.46 / Chapter Chapter 3 --- Results / Chapter 3.1 --- Preparation of SARS CoV main protease and substrate / Chapter 3.1.1 --- Expression and purification of SARS main protease --- p.48 / Figure 3.1. Purification profile of SARS CoV main protease --- p.49 / Chapter 3.1.2 --- Expression and purification of substrate and substrate variants --- p.50 / Figure 3.2. Purification profile of substrate and substrate variants --- p.51 / Chapter 3.2 --- A novel protein-based FRET assay system was established / Chapter 3.2.1 --- "With the cleavage of active main protease, absorbance at 528nm dropped while signal at 485nm were slightly increased" --- p.52 / Figure 3.3. Absorbance at 528nm dropped and 485nm increased with the substrate hydrolysis --- p.53 / Chapter 3.2.2 --- FRET efficiency ratio (528/485) decreased over time --- p.54 / Figure 3.4. FRET efficiency ratio (528/485) decreased over time --- p.55 / Chapter 3.2.3 --- Comparable kcat/Km value of SARS CoV main protease was obtained --- p.56 / Figure 3.5. Catalytic parameter (kcat/ Km) was determined from the slope of straight Line --- p.57 / Chapter 3.3 --- Main protease activity towards substrate variants at different substrate-binding sites (S2'-S2) --- p.58 / Table 3.1. Kinetic parameterrs of 76 substrate variants in descending order --- p.59 / Chapter 3.3.1 --- S2'substrate-binding site --- p.60 / Chapter 3.3.2 --- S1' substrate-b inding site / Chapter 3.3.3 --- S1 substrate-binding site / Chapter 3.3.4 --- S2 substrate-binding site / Figure 3.6. Kinetic analysis of some typical substrate variants against main protease --- p.62 / Figure 3.7. SDS-PAGE analysis of some typical substrate variants against main protease --- p.63 / Chapter Chapter 4 --- Discussion / Chapter 4.1 --- Quantitative and high-throughput analysis by protein-based FRET assay system --- p.64 / Chapter 4.2 --- Substrate specificities of SARS CoV main protease at S2'-S2 subsites / Chapter 4.2.1 --- β-strand conformation was preferred at S2，subsite / Chapter 4.2.2 --- Residues with small aliphatic side chain were preferred at S1 ´ة subsite --- p.65 / Chapter 4.2.3 --- "Glutamine at S1 subsite was absolutely conserved, but alternatives were disclosed" --- p.66 / Figure 4.1. Glutamine was not absolutely conserved in S1 subsite --- p.67 / Chapter 4.2.4 --- Hydrophilic residues were tolerated at S2 subsite --- p.68 / Figure 4.2. Hydrophilic residues were tolerated at S2 subsite --- p.70 / Table 4.1. Summary of types of residues preferred at individual subsites --- p.71 / Chapter 4.3 --- Predicted conformation of substrate towards SARS CoV main protease at S2' and S1' subsites --- p.72 / Figure 4.3. Small residues were preferred at S1´ة subsite and Val at S2' subsite was more favoured than the native one --- p.73 / Chapter Chapter 5 --- Summary --- p.74 / Chapter Chapter 6 --- Future work --- p.75 / References --- p.76