This dissertation reports on the technology of cell-free protein synthesis (CFPS) including 1) stabilized lyophilized cell-free systems and 2) enhanced heterogeneous cell extracts. This work further considers applications of CFPS systems in 1) rapid vaccine development, 2) functional virus-based nanoparticles, 3) site-specific protein immobilization, and 4) expanding the language of biology using unnatural amino acids. CFPS technology is a versatile protein production platform that has many features unavailable in in vivo expression systems. The primary benefit cell-free systems provide is the direct access to the reaction environment, which is no longer hindered by the presence of a cell-wall. The “openness" of the system makes it a compelling candidate for many technologies. One limitation of CFPS is the necessity of freezing for long-term viable storage. We demonstrate that a lyophilized CFPS system is more stable against nonideal storage than traditional CFPS reagents. The Escherichia coli-based CFPS system in this work is limited by the biocatalytic machinery found natively in E. coli. To combat these limitations, exogenous biocatalysts can be expressed during fermentation of cells prepared into extract. We demonstrate that simple adjustments in the fermentation conditions can significantly increase the activity of the heterogeneous extract. Towards virus-based particles and vaccines, we demonstrate that the open nature of CFPS can be utilized for coexpression of virus proteins and self-assembly of virus particles. This technique allows for the rapid production of potential vaccines and novel functional virus-based nanoparticles. Unnatural amino acids expand the effective language of protein biology. Utilizing CFPS as an expression system, we demonstrated that the incorporation of a single specific unnatural amino acid allows for site-specific immobilization, thus stabilizing the protein against elevated temperatures and chemical denaturants. Current unnatural amino acid incorporation technologies are limited to one or few simultaneous incorporations and suffer from low efficiency. This work proposes a system that could potentially allow for upwards of 40 unnatural amino acids to be simultaneously incorporated, effectively tripling the protein code. These projects demonstrate the power and versatility of CFPS technologies while laying the foundation for promising technologies in the field of biotechnology.

<p>  </p> <p>The access of ring junction functionalized 5,6-hydrindanone systems has been elusive in the realm of synthetic methodology, and the functionalization of a pre-built ring system rarely explored. These 5,6-hydridanone systems are prevalent in a variety of terpenoid ring systems, especially that of steroidal molecules. Previous synthetic methods to reach these systems using a Diels-Alder cycloaddition proved to be difficult and lacked labile functional groups that would be useful for substitution after the cycloaddition. The design of the α-nitrile cyclopentenone dienophile allows for both post-cyclization adduct functionalization, as well as lowering the energy barrier of the cycloaddition itself. In this work, it is shown that the Lewis acid promoted Diels-Alder reaction with α-nitrile β-methyl cyclopentenone dienophile can be performed under standard temperatures and pressures unlike previously established methods.1 This reaction can generate four chiral centers in a single synthetic step when the starting materials are prochiral. After the generation of 5,6-hydrindanone systems, radical cleavage of the nitrile functionality also allowed for electrophile trapping at the ring junction. This radical cleavage and electrophile trapping pathway allows for functionalization of a quaternary carbon at the ring junction, a method that should be fruitful in the generation of difficult to synthesize steroidal and other terpenoid molecules.</p> <p>In the work on synthetic cell penetrating peptides, camptothecin whilst a notably effective topoisomerase I inhibitor, has never quite reached it’s potential as a therapeutic due to its poor solubility in living systems. Previously, cationic amphiphilic polyproline helices (CAPH) molecules from the Chmielewski lab have been hydrophobically functionalized through O-alkylation of hydroxyprolines at specific regions within the peptide to generate a hydrophobic face. The combination of the cationic faces and the hydrophobic face have made the CAPH molecules notably cell penetrant and tunable. With camptothecin’s notable insolubility in water, it may serve as valuable surrogate to the hydrophobic groups on CAPH molecules and allowing it to be delivered intracellularly. Using an endogenously cleavable linker, we have worked towards a CPP that acts as a drug delivery vehicle. Acting as a replacement of the hydrophobic residue of a CAPH molecule, camptothecin will be chaperoned into the cell and should be released through the action of intracellular esterases.</p>

Binding of the Rev protein with Rev Response Element (RRE) RNA present in singly- and unspliced mRNA transcripts is necessary for the replication of HIV-1. This interaction transports the mRNA transcripts from the nucleus to the cytoplasm for translation of the necessary structural and enzymatic proteins for the newly budding virus as well as for providing its genetic material. Given the high rate of mutation in HIV-1, the highly conserved and pertinent RRE RNA is of high interest for pharmaceutical intervention. Consequently, a branched peptide library containing unnatural amino acids was developed to target RRE RNA with the goal of increasing stability, potency, selectivity, and in vivo activity for RRE RNA. An unnatural amino acid branched peptide library (46,656 sequences) was synthesized and screened against RRE IIB and several hits in the sub-micromolar regime were found. A number of hits demonstrated selectivity in the presence of other RNAs in addition to two hits, 4A5 and 4B3, significantly inhibiting HIV-1 growth in vitro. These peptides inhibited HIV-1 replication in a concentration dependent manner and were demonstrated to be non-toxic. Further analysis of 4A5 and 4B3 via footprinting and SHAPE-MaP experiments determined that these peptides blocked binding of Rev through binding at the primary and secondary binding sites of RRE RNA. Sphingosine 1-phosphate (S1P) is a signaling molecule that plays a role in various biological processes including immunity, neurogenesis, and angiogenesis. The role S1P plays is largely determined by its location, in which Spinster homolog 2 (spns2) and mfsd2b are the two known transporters. The two transporters exist in different cell types and cellular localizations, with spns2-produced S1P being responsible for trafficking of lymphocytes. As such, spns2 has become of interest for therapeutic targeting in autoimmune and inflammatory diseases. To validate spns2 as a target in pharmaceutical intervention, a series of spns2 inhibitors were developed. A screening of a library of inhibitors found that compound SLP7120922 demonstrated inhibition of spns2 transport activity. The design, synthesis, and biological evaluation of inhibitors based on SLP7120922 is described. Modifications to the lipophilic tail region were performed with one compound 4.40f discovered to be potent, minimally toxic, and active in vivo. A series of modifications to the head region were then conducted that evaluated linear head derivatives with alkyl-, amide-, and amino acid-based groups. A number of compounds are reported that demonstrate good in vitro activity and minimal toxicity with two compounds, 4.48b and 4.52c, showing favorable in vivo activity in mice. / Doctor of Philosophy / Human immunodeficiency virus (HIV-1) has a high rate of mutation, which commonly leads to the need for many types of medications throughout the lifetime of a patient. In order to design a therapeutic that the virus has a low chance of growing resistance to, a target needs to be chosen with a low mutation rate. One such target is the Rev Response Element (RRE) RNA and it is necessary for the virus to replicate. A protein named Rev binds to RRE RNA in order for RRE to carry out its pertinent function. To block this function we have chosen branched peptides to target the RNA. Peptides are made of the same building blocks of proteins, but are much shorter than proteins. The peptides described here are made up of modified building blocks, called unnatural amino acids. This work describes the generation of an unnatural amino acid branched peptide library and how it was screened in order to find branched peptides that bind RRE RNA. Many peptides were found to bind RRE RNA but two in particular, 4A5 and 4B3, were the best binders that inhibited HIV-1 growth. The remainder of the work describes how these peptides bind to RRE RNA, while demonstrating that they are non-toxic and bind HIV-1 in a concentration dependent manner. A transporter protein termed Spinster homolog 2 (spns2) transports a signaling molecule known as sphingosine 1-phosphate (S1P). For our immune system to function properly, spns2 has to transport S1P to the appropriate places to signal to immune cells. Unfortunately, this is a problem in autoimmune and inflammatory diseases, such as multiple sclerosis, due to these diseases having an overactive immune system. A potential way to treat these diseases would be by inhibiting spns2. This work describes the design, synthesis, and biological evaluation of spns2 inhibitors. Many compounds were found to inhibit spns2 to a degree, but three compounds, in particular, show potent and effective inhibition in mice.

This study showed that health equity must be achieved through education, awareness, and advocacy. A structured program must be put in place to provide accountability towards achieving health equity within organizations, communities, cites, and states. In Virginia, the Health Equity Campaign was a program put in place to provide such accountability to the citizens of Virginia. This study attempted to evaluate the Health Equity Campaign implemented by the Virginia Department of Health Office of Minority Health and Public Health Policy Division of Health Equity in order to get all Virginians to become advocates for health equity in their organizations, communities, neighborhoods. Organizational/group leaders were interviewed in addition to surveying various staff members. This study provides a detailed description of the strength of the Health Equity Campaign's ability to promote education and awareness about health equity and why many participants found it difficult to transition from motivation to advocacy. / Ph. D.

Conjugation reactions on proteins have been used to access various post-translational modifications, for targeted delivery of drugs, for microscopy, and in studying receptor-ligand interactions. However, the ability to modify native proteins is constrained by the reactive functionalities of naturally occurring amino acids. This has driven research into the incorporation of unnatural amino acids (UAAs) into proteins. Research in this area has been motivated both by the possibility of increasing the breadth of chemical techniques for protein modification by introducing novel 'bio-orthogonal' reactive groups via UAA incorporation, as well as generating well-defined conjugates by the site-selective incorporation of these UAAs into proteins. The objective of this thesis is to both expand the diversity of UAAs for access to new metal-mediated reactions on proteins, as well as to utilise these reactions to reveal functional information about a range of biological systems. A brief introduction into current protein conjugation and UAA incorporation methods will be made in Chapter 1. In Chapter 2, the genetic incorporation of alkene-bearing UAAs into recombinant proteins expressed in both bacterial and mammalian systems is discussed. This technique is demonstrated to enable Ru-catalysed olefin cross-metathesis (CM) reactions on the resultant proteins. This work builds upon previously established methods to chemically incorporate CM handles onto proteins. The rational design of UAAs, as well as assays and modelling studies to screen them for recognition by the cellular incorporation machinery are discussed in detail. The expression of a range of alkene-tagged recombinant proteins, their complete characterisation, as well as the development of a more general protocol for on-protein CM is elucidated. In Chapter 3, the utility of UAA incorporation to probe mammalian cell translation systems is examined. Incorporation of an azide-bearing UAA, in addition to heavy stable-isotope labelled amino acids is used to uncover a previously unreported system of protein synthesis in mammalian cell nuclei, along with rapid metabolic degradation of the synthesised peptides. Various orthogonal methods for the detection of this system as well as possible reasons for its conservation are discussed. In Chapter 4, UAA incorporation and metal-mediated bioconjugation reactions are utilised in the development of a novel and generally applicable proteomics technique. This technique is used to determine quantitative changes in cell proteomes in response to external stimuli, and may be applied to systems to which traditional proteomics techniques cannot, such as ex vivo primary cells. Finally, in Chapter 5, further applications of UAA incorporation are discussed. Preliminary results are reported in efforts to use UAAs in the vibrational Raman microscopic imaging of biological systems, in generating HIV vaccines, and inducing T-cell stimulation.

Le travail présenté dans ce manuscrit a pour objectif la synthèse d'analogues sélectifs NTS2 de la neurotensine et l'étude de leur potentiel analgésique. La faible biodisponibilité de la neurotensine, caractérisée par sa courte durée de demi-vie et le non passage de la barrière hémato-encéphalique, est l'un des problèmes majeurs pour son activité biologique. Dans un premier temps, nous avons développé la synthèse d'aminoacides non naturels hydrophobes : la (triméthyl)silylalanine, des glycines N-substituées et des α-aminoacides insaturés, alliant la non reconnaissance par les enzymes et l'amélioration du passage des membranes. Puis, certains d'entre eux ont été incorporés à la séquence minimale active NT[8-13] afin d'évaluer leur impact sur l'affinité et/ou l'activité de ce fragment. Pour cela, nous avons synthétisé une série de peptides et pseudopeptides afin d'étudier d'une part leur affinité vers les récepteurs NTS1 et NTS2 et, pour certains d'entre eux, leur activité in vivo par des expérimentations sur le modèle de la douleur en collaboration avec l'université de Sherbrooke. Enfin, nous avons préparé une première série d'analogues de la neuromédine, agoniste des récepteurs de la NT et métabolite issu d'un précurseur commun, la pro-neurotensine. / The aim of this work concerns the synthesis of selective NTS2 neurotensin analogues as potent antinociceptive agents followed by biological activities studies. Poor bioavailability of neurotensin is one of the major obstacles for therapeutic effects. Indeed, this tridecapeptide has a short half-life time due to enzymatic degradation and is too hydrophilic to cross blood-brain barrier. First, we developed different methods to obtain hydrophobic unnatural amino acids like (trimethyl)silylalanine, N-substituted glycines and unsatured α-amino acids. All these peptide building blocks combine lipophilic properties facilitating membrane permeability and enzymatic unrecognition advantages. Some of them have been incorporated in the C-terminal active fragment NT[8-13] in order to evaluate their impact on affinity and/or biological activities. Thus, a series of new peptides and pseudopeptides was prepared and in vivo behavior was studied using a pain model designed in Sherbrooke university. Finally, we synthesized new analogues of neuromedin which is a neurotensin agonist issued from a common precursor, the pro-neurotensine.

No description available.

Doctor of Philosophy / Department of Chemistry / Duy H. Hua / Three research projects were carried out and they are described below. The synthesis of substituted phenolic compounds including halogenated di- and trihydroxybenzenes, aminophenols, and substituted di-tert-butylphenols are described. Redox potentials of the synthesized molecules along with various known laccase substrates were measured, and an inverse relationship between the oxidation potential and the efficiency of oxidation by laccase of halogenated hydroxybenzenes and aminophenols is demonstrated. The synthesized substituted phenols were found to be substrates but not inhibitors of laccase. We discovered a new class of di-tert-butylphenols compounds that inhibits the growth of mosquito larvae at low concentrations. Compound 17, 2,4-di-tert-butyl-6-(3-methyl-2-butenyl) phenol caused greater than 98% mortality of third-instar larvae of Anopheles gambiae in the concentration of 0.18 µM. These compounds do not inhibit laccases. It appears that they affect a new target of the mosquito that is different from those of currently existing pesticides. Two anti-Alzheimer molecules, CP2 and TP70, discovered in our laboratory were studied for their pharmacokinetics and distribution. The distribution of CP2 and TP70 in mouse brain region and various tissues of mice were examined. HPLC analysis revealed that CP2 treatment in primary neurons accumulates in mitochondria fraction. Similarly, the amount of CP2 in the brain tissue from wild type and APP/PS1 mice treated with 25 mg/kg/daily for 2 months also have the highest concentration in the mitochondria fractions in the hippocampus. The results show that CP2 and TP70 can penetrate the blood brain barrier and accumulate in the tissue in significant amounts. Pharmacokinetics and bioavailability of compound TP70 were determined. Area under the curve and bioavailability value F were calculated, and data show that TP70 has a good PK profile and bioavailability. For the preparation of a novel tripeptidyl norovirus 3C-like protease (3CL[superscript]pro) inhibitor, the P3 unnatural amino acid, (S)-3-hydroxyphenylalanine was synthesized. The P3 is designed to increase the polarity with the addition of the alcohol group. After combining the P3 unnatural amino acid with the P1 and P2 to form the novel tripeptidyl compound, a study comparing the relations between the structure and its activity (SAR) will confirm whether prediction is correct in our pursuit for an antiviral therapeutic drug in the form of a protease inhibitor.

Les protéines membranaires comme les récepteurs, les canaux ioniques et les transporteurs possèdent des rôles cruciaux dans les processus biologiques tels que la signalisation physiologique et les fonctions cellulaires. La description dynamique et fonctionnelle des structures protéiques est fondamentale pour comprendre la plupart des processus concernant les macromolécules biologiques. L'incorporation, dans des protéines, d'acides aminés non naturels (Uaas) possédant des propriétés physiques ou chimiques spécifiques fournit un puissant outil pour définir la structure et la dynamique de protéines complexes. Ces sondes permettent le suivi et la détection en temps réel de la conformation des récepteurs et des complexes de signalisation. Les approches d'expansion du code génétique ont permis l'incorporation d'Uaas servant de sondes dans des protéines avec une précision moléculaire. L'expansion héréditaire du code génétique peut permettre d'étudier la biologie des protéines de manière systémique.Avec cette stratégie, des Uaas capables de photopontage ont été utilisés pour étudier la relation structure/fonction des Protéines G Couplées aux Récepteurs (GPCR), telles que l'identification de la liaison du ligand ou des interactions protéine-protéine, en détectant les changements dynamiques avec les Uaas spectroscopiques et l'étiquetage bioorthogonal. Sur la base d'applications relativement bien établies d'Uaa dans les GPCR, ici, les analyses fonctionnelles sont combinées à l'incorporation génétique d'un Uaa photosensible spécifique au site, p-azido-L-phénylalanine (AzF) dans d'autres protéines membranaires, pour détecter la protéine, les changements conformationnels et les interactions protéiques. Contrairement à d’autres molécules photosensibles qui permettent aux protéines de répondre à la lumière, l'insertion des Uaas directement dans la chaine d’acides aminés offre des possibilités uniques pour le photo-contrôle de la protéine. Les aspects dynamiques de l'allostérie sont plus difficiles à visualiser que les modèles structuraux statiques. Une stratégie photochimique est présentée pour caractériser la dynamique des mécanismes allostériques des récepteurs NMDA neuronaux (NMDAR). Ces récepteurs appartiennent à la famille des canaux ioniques activés par le glutamate et portent la transmission synaptique excitatrice rapide associée à l'apprentissage et à la mémoire. En combinant le balayage AzF et un test fonctionnel résistant à la lumière, nous avons pu apporter des éléments permettant de mieux comprendre la dynamique des interfaces NTD (N-Terminal Domain des NMDAR) ainsi qu’un nouveau mécanisme de régulation allostérique, améliorant notre compréhension de la base structurale du mécanisme d’activation et de modulation des récepteurs NMDA.Outre l'incorporation de l’Uaa photopontant AzF dans les récepteurs neuronaux pour détecter l'effet fonctionnel, AzF a été appliqué pour piéger des interactions faibles et transitoires entre protéines dans un transporteur d'acides aminés LAT3, impliqué dans le cancer de la prostate. Les techniques de dépistage ont été établies en appliquant un photo-cross-linker positionné dans la protéine pour examiner les interactions entre LAT3 et les interacteurs inconnus et fournir des indices d'identification des partenaires de liaison.Dans l'ensemble, ce travail dévoile de nouvelles informations sur la modulation allostérique de l'activité du récepteur NMDA et sur les interactions protéines-protéines.. Les résultats pourraient fournir de nouvelles informations structurales et fonctionnelles et guider le dépistage de composés thérapeutiques pour des maladies associées au dysfonctionnement de ces protéines membranaires. / Membrane proteins including receptors, channels and transporters play crucial roles in biological processes such as physiological signaling and cellular functions. Description of dynamic structures and functions of proteins is fundamental to understand most processes involving biological macromolecules. The incorporation of unnatural amino acids (Uaas) containing distinct physical or chemical properties into proteins provides a powerful tool to define the challenging protein structure and dynamics. These probes allow monitoring and real-time detection of receptor conformational changes and signaling complexes. The genetic code expansion approaches have enabled the incorporation of Uaas serving as probes into proteins with molecular precision. Heritable expansion of the genetic code may allow protein biology to be investigated in a system-wide manner.With this strategy, photocrosslinking Uaas have been used to study GPCR structure/function relationship, such as identifying GPCR-ligand binding or protein-protein interactions, detecting dynamic changes with spectroscopic Uaas and bioorthogonal labeling. Based on relatively well-established applications of Uaa in GPCRs, here, functional assays are combined with the site-specific genetic incorporation of a photo-sensitive Uaa, p-azido-L-phenylalanine (AzF) into other membrane proteins, to probe protein conformational changes and protein interactions. Unlike photo-sensitive ligands that enable proteins in response to light, the site-specific insertion of light-sensitive Uaas facilitates directly light-sensitive proteins. Dynamic aspects of allostery are more challenging to visualize than static structural models. A photochemical strategy was presented to characterize dynamic allostery of neuronal NMDA receptors (NMDARs), which belong to the ionotropic glutamate receptor channel family and mediate the fast excitatory synaptic transmission associated with learning and memory. By combining AzF scanning and a robust light-induced functional assay the dynamics of NMDAR N-terminal domain (NTD) interfaces and novel allosteric regulation mechanism were uncovered, improving our understanding of the structural basis of NMDAR gating and modulation mechanism.Besides incorporation of photo-cross-linker AzF into neuronal receptors to detect the functional effect, AzF was used to trap transient and weak protein-protein interactions in an amino acid transporter LAT3, which is critical in prostate cancer. Screening technique was established by applying genetically encoded photo-cross-linker to examine interactions between LAT3 and unknown interactors and provide clues to identify the binding partners.Overall, the work reveals new informations about the allosteric modulation of channel activity and proteins interactions. These light-sensitive proteins facilitated by site-specific insertion of light-sensitive Uaas enable profiling diversity of proteins. The results will provide novel structural and functional information and may guide screening of therapeutic compounds for diseases associated with malfunctioning of these membrane proteins.

No description available.