The first half of this dissertation describes the synthesis and biological activities of a series of amino aldehydes; which were derivatives of the basic amino acids, arginine, lysine and ornithine. The synthesis of the amino aldehydes was complicated by the difficulty of producing an intermediate oxidation state (the aldehyde) in the presence of two other functional groups (the α-amino, and the side chain functionality). The amino aldehydes were of biological interest due to the fact that they were inhibitors of the proteolytic enzymes called kallikreins. The kallikreins are known to be involved with the renin-angiotensin system, arginine vasopressin, and the prostaglandins, in the regulation of blood pressure. The aldehydes were assayed for their ability to inhibit the kallikrein-mediated production of kinins, and by the inhibition of the cleavage of Nᵅ-tosyl arginine methyl ester (TAME) to the carboxylic acid. Two of the amino aldehydes (Nᵅ-t-Boc-Nᴳ-nitro-L-argininal and Nᵅ-t-Boc-Nᴳ-tosyl-L-argininal) were effective inhibitors in both bioassays at micromolar concentrations. The second part of the dissertation details the development of two syntheses of β-substituted analogues of cysteine. The first method was based on sulfenylation of Nᵅ-formyl-α, β-dehydro amino acid esters, followed by protection of the sulfhydryl group as the benzyl or para-methylbenzyl thioether. The Nᵅ-formyl and ester groups were cleaved by acidic hydrolysis, and the amino group was then blocked as the t-butyloxycarbonyl derivative. This procedure gave cysteine analogues which were suitable for direct use in solid phase peptide synthesis. A second, more efficient preparation of the cysteine analogues was based on the conjugate addition of lithium benzylthiolate (or lithium para-methylbenzylthiolate) to the Nᵅ-formyl-α, β-dehydroamino acid esters. This synthesis was more efficient since the cysteine analogues were generated directly in S-protected form. The fully protected intermediates were deprotected at the amino and carboxyl groups, followed by treatment with di-tert-butyl dicarbonate. The Nᵅ- t-Boc-β-S-benzyl cysteine analogues (or Nᵅ -t-Boc-β-S-para-methylbenzyl) also were suitable for direct use in solid phase peptide synthesis.

Multiple sclerosis (MS) is a chronic central nervous system disease featuring exacerbations of inflammation and demyelination that cause progressively debilitating clinical effects over time. Current treatments for multiple sclerosis are limited in their ability to impact overall disease progression. Research aimed at generation of novel potential therapeutics for MS is needed. Recently, kallikrein 6 (KLK6), a member of the kallikrein (KLK) family of secreted serine proteases, was found to be elevated in the cerebrospinal fluid and brain of MS patients. The fifteen known tissue-based KLKs cleave proteins through a similar mechanism, but have different binding pocket specificity, diverse localization in human tissues, and multiple biological functions. KLKs have been linked to normal human physiology (e.g. KLK4, enamel formation) and disease (e.g. KLK3, prostate cancer). KLK6 is one of the highest expressed serine proteases in the healthy human brain and is expressed predominately in mature oligodendrocytes in both human and mouse brain. The role of KLK6 in oligodendrocyte maturation, myelination, and disease is not fully understood. To evaluate the role of KLK6 in oligodendrocyte maturation, I used a pluripotent in vitro primary cell system to assess the impact of exogenous KLK6 and modulators of the KLK6 pathway on oligodendrocyte maturation. I demonstrate that signaling through KLK6 decreases the number of mature oligodendrocytes in culture, whereas blockade of KLK6 signaling increases the number of mature oligodendrocytes in culture in the presence of triiodothyronine higher than either agent alone. This work suggests that KLK6 modulation impacts oligodendrocyte maturation. To understand the potential impact of KLK6 pathway inhibition on remyelination, I used the toxin cuprizone to induce demyelination in mice. I found that animals treated with a KLK6 inhibitor had increased myelin staining in the corpus callosum compared to vehicle-treated. This work suggests that KLK6 modulates oligodendrocyte maturation and myelination and may be relevant for improving myelin-related therapeutic outcomes, particularly in multiple sclerosis. / 2019-06-12T00:00:00Z

Au cours de cette thèse, nous nous sommes intéressés à l’implication de la kallicréine-12 (KLK12), une protéase à sérine, dans la cancérogenèse pulmonaire. La KLK12 est connue comme étant surexprimée dans les tumeurs pulmonaires non à petites cellules mais son rôle dans la cancérogenèse n’est pas clairement établi. Nos travaux ont permis de lui attribuer un effet proangiogénique vis-à-vis des cellules endothéliales pulmonaires. En effet, la KLK12 peut stimuler la migration des cellules endothéliales pulmonaires en modifiant l’architecture de la matrice extracellulaire. D’autre part, elle est impliquée dans la régulation de la biodisponibilité de facteurs de croissance associés à l’angiogenèse tels que le Platelet-derived growth factor-B. De plus, nos travaux ont permis d’identifier une possible régulation de l’expression de la KLK12 par l’hypoxie, ce qui expliquerait sa surexpression dans les tumeurs pulmonaires et conforterait son implication dans l’angiogenèse. La confirmation in vivo des mécanismes d’action de la KLK12 pourrait permettre d’envisager son utilisation comme cible thérapeutique afin de réguler la néoangiogenèse tumorale. / In this thesis, we studied the involvement of the serine protease kallikrein-12 (KLK12), in lung carcinogenesis. The KLK12 is known to be overexpressed in non-small cell lung cancer but its role in carcinogenesis is not clearly established. Our work shows that it possesses a proangiogenic effect on pulmonary endothelial cells. Indeed, KLK12 stimulates lung endothelial cells migration notably by modulating the extracellular matrix architecture. On the other hand, KLK12 regulates the bioavailability of growth factors associated with angiogenesis such as plateletderived growth factor-B. In addition, our work has identified a possible regulation of the expression of KLK12 by hypoxia, which would explain its overexpression in lung tumors and would reinforce its involvement in angiogenesis. The confirmation in vivo of these mechanisms could help consider KLK12 as a therapeutic target for regulating tumor angiogenesis.

Η καλλικρεΐνη 6 (του ανθρώπου συμβολίζεται ως ΚLK6, ενώ του ποντικού ως Klk6), φαίνεται πως σχετίζεται με νευροεκφυλιστικές ασθένειες, όπως η σκλήρυνση κατά πλάκας και η νόσος του Parkinson, καθώς επίσης και με διάφορους τύπους καρκίνου. Επομένως, η μελέτη του ρόλου που διαδραματίζει η ΚLK6 στις παραπάνω ασθένειες σε πειραματικά πρότυπα ποντικού, μπορεί να χρησιμοποιηθεί για την κατανόηση αυτών των ασθενειών και στον άνθρωπο. Στην παρούσα εργασία αρχικά παρήχθη η ώριμη Κlk6 ποντικού ως ανασυνδυασμένη πρωτεΐνη στο σύστημα έκφρασης του μεθυλοτροφικού ζυμομύκητα Pichia pastoris KM71 και δείχθηκε ότι η παραχθείσα πρωτεΐνη ήταν ενζυμικά δραστική. Το cDNA που κωδικοποιεί την ώριμη Klk6 πρωτεΐνη απομονώθηκε με RT-PCR από τον εγκέφαλο ποντικού C57BL6. Το προϊόν πολλαπλασιάστηκε με αντίδραση PCR και μετά από πέψη με τα περιοριστικά ένζυμα XhoI και EcoRI κλωνοποιήθηκε στον φορέα pPIC9. Ο ζυμομύκητας Pichia pastoris KM71 μετασχηματίσθηκε με το ανασυνδυασμένο πλασμίδιο pPIC9/ώριμη Klk6 με τη μέθοδο των σφαιροπλαστών. Από τους ανασυνδυασμένους κλώνους του ζυμομύκητα που μετασχηματίσθηκαν με το πλασμίδιο έκφρασης απομονώθηκε πλασμιδικό DNA και η ορθή κλωνοποίηση και η απουσία μεταλλάξεων στην προς έκφραση αλληλουχία DNA επιβεβαιώθηκαν με αλληλούχηση. Στη συνέχεια, οι ανασυνδυασμένοι κλώνοι αναπτύχθηκαν σε υγρή καλλιέργεια και ελέχθηκε στο υπερκείμενο η παραγωγή ανασυνδυασμένης Klk6, δεδομένου ότι το σύστημα έκφρασης έχει σχεδιασθεί ώστε η ανασυνδυασμένη πρωτεΐνη να εκκρίνεται. Η ανασυνδυασμένη Klk6 απομονώθηκε από το υπερκείμενο και καθαρίσθηκε με χρωματογραφία υδρόφοβων αλληλεπιδράσεων ανοικτής στήλης. Μετά τον καθαρισμό, η απόδοση της παραγωγής ήταν 4,16 mg ανασυνδυασμένης Klk6 πρωτεΐνης ανά λίτρο (lt) αρχικής καλλιέργειας Η ενζυμική δραστικότητα της ανασυνδυασμένης Klk6 πρωτεΐνης ελέγχθηκε με ζυμογραφία ζελατίνης και καζεΐνης (ως υποστρώματα), καθώς και με βάση την ικανότητα υδρόλυσης χρωμογόνων συνθετικών πεπτιδικών υποστρωμάτων και πρωτεϊνικών υποστρωμάτων. Στη συνέχεια, πραγματοποιήθηκε η παραγωγή πολυκλωνικού αντισώματος ειδικού για την Klk6 πρωτεΐνη του ποντικού. Για την ανοσοποποίηση χρησιμοποιήθηκαν συνθετικά πεπτίδια με αλληλουχία που αντιστοιχεί σε δύο μη επικαλυπτόμενες περιοχές της Klk6, οι οποίες -κατά την υπολογιστική πρόβλεψη- χαρακτηρίζονται από υψηλή υδροφιλικότητα και αντιγονικότητα. Για την ανοσοποίηση, τον έλεγχο του τίτλου και τον καθορισμό των αντισωμάτων ακολουθήθηκαν καθιερωμένα πρωτόκολλα. Μετά τον καθαρισμό το κλάσμα των IgG αντισωμάτων αξιολογήθηκε ως προς την εξειδίκευση και τη συγγένεια έναντι της Klk6 ποντικού, χρησιμοποιώντας αρχικά την ανασυνδυασμένη Klk6 πρωτεΐνη, που παρήχθη όπως περιγράφηκε. Βρέθηκε ότι το παραχθέν πολυκλωνικό αντίσωμα αναγνωρίζει την πρωτεΐνη με υψηλή εξειδίκευση και ευαισθησία και το όριο ανίχνευσης προσδιορίσθηκε με ανοσοαποτύπωση πρωτεϊνών στα 50 ng. Τέλος, με RT-PCR αναλύθηκε το προφίλ έκφρασης της Klk6 σε ιστούς του ποντικού χρησιμοποιώντας εκκινητές ειδικούς για το γονίδιο Klk6. Χρησιμοποιώντας ολικά πρωτεϊνικά εκχυλίσματα από τους ιστούς εκείνους του ποντικού που βρέθηκε ότι εκφράζουν την Klk6, δείξαμε ότι το παραχθέν αντι-Klk6 πολυκλωνικό αντίσωμα αναγνωρίζει την ενδογενή Klk6 πρωτεΐνη με υψηλή ευαισθησία και ειδικότητα. Συνοπτικά, στην παρούσα εργασία παρήχθη με μεγάλη απόδοση ανασυνδυασμένη Klk6 πρωτεΐνη και με ενζυμικές δοκιμές δείχθηκε ότι είναι ενζυμικά δραστική, δηλαδή είχε την προβλεπόμενη πρωτεολυτική δράση. Επίσης, παρήχθη το πολυκλωνικό αντίσωμα αντι-Klk6 και δείχθηκε ότι αναγνωρίζει με υψηλή συγγένεια και ειδικότητα τόσο την ανασυνδυασμένη όσο και την ενδογενή Klk6 πρωτεΐνη σε ιστούς ποντικού και ως εκ τούτου θα αποτελέσει πολύτιμο εργαλείο για να μελετηθεί σε πρότυπα ποντικού ο ρόλος της πρωτεάσης Klk6 και η συμμετοχή της σε σηματοδοτικά μονοπάτια που σχετίζονται με σοβαρές ασθένειες, όπως η σκλήρυνση κατά πλάκας και η νόσος του Parkinson. / The kallikrein-related peptidase 6 (KLK6 for human; Klk6 for mouse) has been implicated in neurodegenerative diseases including multiple sclerosis and Parkinson’s disease and in various types of cancer. Therefore, the investigation of the role(s) of Klk6 in mouse models used for the study of the aforementioned human diseases becomes a necessity. First in this study, active recombinant mouse Klk6 protein was produced in Pichia pastoris KM71. The cDNA encoding for the mature mouse Klk6 protein was obtained by RT-PCR from RNA extracted from mouse C57BL6 brain. The PCR product was digested with XhoI and EcoRI, purified and subsequently cloned into the pPIC9 expression vector. The methylotrophic yeast strain Pichia Pastoris KM71 was transformed with the pPIC9/mature Klk6 construct, linearized with SalI, with the spheroplast method. Recombinant yeast clones transformed with the expression construct pPIC9/mature Klk6 were identified, confirmed by DNA sequencing and grown in liquid culture for recombinant protein production. Recombinant Klk6 was isolated from the yeast culture supernatant and was purified by hydrophobic interaction chromatography (HIC). The yield of recombinant protein production was 4.16 mg/lt culture after purification. Then, rKlk6 was characterized, in terms of proteolytic activity, by gelatin and casein zymography and by digestion of chromogenic synthetic peptide substrates and protein substrates. Νo antibody is currently available that is highly specific for mouse Klk6. Here, a novel rabbit anti-peptide polyclonal for mouse Klk6 was generated. Peptides corresponding to two non-overlapping Klk6 sequences of high hydrophilicity and predicted antigenicity were synthesized, conjugated to keyhole limpet hemocyanin (KLH) and used for immunization. The specificity and affinity of the purified polyclonal was assessed against active recombinant mouse Klk6 protein produced in Pichia pastoris KM71 as described, and the detection limit was determined at 50 ng by Western blot. Finally, the expression of Klk6 in mouse tissues was analyzed by semi-quantitative RT-PCR using gene-specific primers. Using whole extracts of Klk6 expressing mouse tissues, we showed that the purified anti-Klk6 polyclonal (IgG fraction) recognizes the endogenous Klk6 protein with a high sensitivity and specificity. Conclusively, the produced αντι-Klk6 polyclonal should be a valuable tool in studies employing mouse models in order to decipher the putative role(s) of Klk6 in signaling pathways involved in major human diseases, such as the multiple sclerosis and Parkinson’s disease.

Submitted in part fulfillment for the Degree of Master of Technology: Biotechnology, Durban Institute of Technology, 2003. / Evidence suggests that the induction of tissue kallikrein, and the subsequently formed kinins, enhances proliferation of tumour cells because of their mitogenic property. Additionally, the kinin peptides are believed to promote the invasion of normal tissue by tumour cells. TGF-l is a potent inhibitor of the growth of renal epithelial cells, and is a classical anti-mitogen, which is central to many of its antiproliferative effects. No studies thus far have been performed, as to whether the proposed anti-mitogenesis ofTGF-1 has a regulatory effect on the cell proliferative action of kinins on renal epithelial and carcinoma cells. / M

The family of human kallikrein-related peptidases (KLKs) numbers 15 serine proteinases implicated in tumour progression. Despite the wide tissue distribution of KLKs and the numerous reports of their differential expression in pathological settings, the signalling mechanism(s) whereby these enzymes regulate tissue function are not yet known. Further, knowledge of the levels of their activity, as well as of their potential endogenous targets, has only been extracted from in vitro studies and cell culture systems. We hypothesized that KLKs can trigger tumour signalling via proteinase-activated receptors (PARs), a family of G-protein-coupled receptors. To test our hypothesis, we evaluated the ability of KLKs 5, 6, and 14: to activate or prevent signalling via PARs 1, 2, and 4 in cells and tissues expressing these receptors. Further, we used a novel activity-based probe approach, coupled with conventional immunoassay (ELISA), to determine the abundance of active KLK6 relative to total immunoreactive KLK6 in cancer-related biological fluids. We concluded that KLKs can regulate multiple signalling pathways triggered by PARs 1, 2, and 4, resulting in calcium release, platelet aggregation and vascular relaxation, and they can cause murine inflammation. Further, our activity-based ELISA demonstrated the presence of active KLK6 in ovarian cancer ascites fluids and cancer cell supernatants. We, therefore, suggest that tumours can produce active KLKs, which can potentially control tumour behaviour by regulating PAR activity.

Le système kallicréine-kinines (SKK) est un système peptidique vasodilatateur. Les métabolites actifs du système, les kinines, sont produites par la kallicréine tissulaire (TK), et agissent via leurs deux récepteurs, B2 et B1. Le SKK a été impliqué dans les processus physiopathologiques conduisant au diabète de type 2. Son rôle est bien établi dans la protection des complications cardiovasculaires et rénales du diabète. Nous avons étudié le rôle du SKK dans le développement des anomalies métaboliques liées à l'obésité en utilisant des souris déficientes en TK dans deux modèles d'obésité (mutation ob/ob et régime gras). Nous n'avons pas mis en évidence d'effet de la déficience en TK sur les anomalies glucidiques dans ces deux modèles. Chez l'homme, nous avons étudié l'effet d'un polymorphisme génétique de la TK dans une cohorte de 4843 sujets de la population générale suivi pendant 9 ans. Nous n'avons pas observé d'effet d'un déficit partiel en activité TK sur l'apparition des troubles glucidiques.Ensuite, nous avons étudié l'effet de la stimulation du SKK par des agonistes spécifiques de chaque récepteur lors d'une ischémie reperfusion cardiaque. Chez les souris non diabétiques, l'agoniste B2 réduit la taille de l'infarctus. L'agoniste B1 n'a pas d'effet. Chez les souris diabétiques, l'agoniste B2 n'a pas d'effet. En revanche, l'agoniste B1 diminue la taille de l'infarctus. On observe une induction de la synthèse du B1R dans le c¿ur diabétique.Nos travaux clarifient le rôle du SKK dans le développement du diabète et de ses complications cardiaques. L'effet des agonistes ouvre une nouvelle piste thérapeutique dans la prise en charge des du syndrome coronarien aigu. / Kallikrein-kinin system (KKS) is a vasodilator peptide system. Kinins, the active peptides, are produced by tissue kallikrein (TK), and act via their two receptors, B1 and B2. KKS was involved in the pathophysiological process leading to type 2 diabetes. Its role is well established in the protection of cardiovascular and renal complications of diabetes. We studied the role of SKK in the development of metabolic abnormalities associated with obesity using TK deficient mice in two models of obesity (Ob/Ob and high fat diet). We did not observed any effect of TK deficiency on metabolic parameters in these two models. In humans, we studied the effect of a polymorphism of TK in a population-based cohort of 4843 subjects followed for 9 years. We did not observe any effect of a partial deficiency in TK on the occurrence of metabolic disorders. Next, we studied the effect of specific agonists of B1 and B2 receptors in cardiac ischemia reperfusion injury. In non-diabetic mice, the B2 agonist reduces infarct size. Agonist B1 has no effect. In diabetic mice, B2 agonist had no effect. In contrast, B1 agonist reduces infarct size. Overexpression of B1R is observed in the diabetic heart. Our work clarifies the role of SKK in the development of diabetes and its cardiac complications. Agonists of kinins receptors could be a new therapeutic approach in the management of acute coronary syndrome.

Im Blutplasma und auf Zelloberflächen bildet H-Kininogen entweder mit dem Blutgerinnungsfaktor XI oder Plasmakallikrein Komplexe. Die beiden Proteasenvorstufen binden über ihre homologen schweren Ketten, die jeweils aus vier Apple Domänen bestehen (F1-F4 bei Faktor XI und P1-P4 bei Kalllikrein), an HK. Die Kalllikrein/Kininogen Interaktion wird über Domäne P2 vermittelt. Im Gegensatz dazu soll FXI über F1 an Kininogen binden. Gegenstand der vorliegenden Arbeit ist die Lokalisation der Kininogen-Bindungsstelle des Faktors XI und ein funktioneller Vergleich der Kalllikrein/Kininogen und Faktor XI/Kininogen Komplexe. Es zeigt sich, dass die relative Bindungsaffinität von HK an rekombinante Faktor XI-Einzeldomänen in der Reihenfolge F2 >> F4 > F1 >> F3 abfällt. Die Bedeutung der F2 Domäne für die Kininogen Bindung wird durch den monoklonale Antikörper αP2 unterstrichen, der die Faktor XI/Kininogen und die Kalllikrein/Kininogen Bindung mit einem apparenten IC50 von 8 nM blockiert und dessen Epitop auf die F2 Domäne kartiert wird. Eine Thrombozyten-spezifische Faktor XI-Splicevariante, der die N-terminale Hälfte der F2 Domäne fehlt, bindet 5-fach schlechter als Faktor XI an Kininogen. Nach Aktivierung wird Kallikrein und ein chimäres Faktor XI-Protein, bei dem F2 durch P2 ersetzt wurde, in P2 gespalten, was zur Verlust der Bindungsaffinität zu Kininogen führt. Im Gegensatz bleibt die Bindung von aktiviertem Faktor XI oder einem chimärem Kalllikrein-Protein, bei dem die P2 Domäne durch F2 ersetzt wurde, nach Aktivierung an Kininogen gebunden. Diese Daten zeigen, dass Faktor XI und Kallikrein über ihre Domänen 2 an Kininogen binden. Trotz homologer Bindungsmotive unterscheiden sich Faktor XI/Kininogen und Kallikrein/Kininogen Komplexe in ihrer Stabilität nach Aktivierung. Die Daten tragen dazu bei, die Regulation der Kallikrein-vermittelten Bradykininbildung bei Entzündungsprozessen und die Faktor XI-getriebene Fibrinbildung besser zu verstehen. / Factor XI (FXI), the zymogen of the blood coagulation protease FXIa, and the structurally homologous protein plasma prekallikrein circulate in plasma in non-covalent complexes with H-kininogen (HK). HK binds to the heavy chains of FXI and of prekallikrein. Each chain contains four apple domains (F1 - F4 for FXI; P1 - P4 for prekallikrein). Previous studies had indicated that the HK binding site on FXI is located in F1, while the major HK binding site on prekallikrein is on P2. To determine the contribution of each FXI apple domain to FXI/HK complex formation, we examined binding of recombinant single apple domain-tPA fusion proteins to HK. The order of affinity from highest to lowest is F2 >> F4 > F1 >> F3. Monoclonal antibodies against F2 are superior to F4 or F1 antibodies as inhibitors of HK binding to FXI. Antibody αP2, raised against prekallikrein, cross-reacts with FXI F2 and inhibits FXI/HK binding with an IC50 of 8 nM. HK binding to a platelet specific FXI variant lacking the N-terminal half of F2 is reduced > 5-fold compared to full-length FXI. A chimeric FXI molecule in which F2 is replaced by P2, is cleaved within P2 during activation by factor XIIa, resulting in greatly reduced HK binding capacity. In contrast, wild-type FXI is not cleaved within F2, and its binding capacity for HK is unaffected by factor XIIa. Our data show that HK binding to FXI involves multiple apple domains, with F2 being most important. The findings demonstrate a similarity in mechanism for FXI and prekallikrein binding to HK. Although the zymogens complex HK via homologous binding motives the stability of FXI/HK and kallikrein/HK complexes is largely diffent following activation. The data may help to understand kallikrein-driven bradykinin formation in inflammation and FXI-mediated fibrin generation in thrombosis.

In this work, we examine the structure and function of two important human proteins. The first is human kallikrein 6 (hK6), which is a newly identified enzyme in the serine proteinase family that is expressed in the central nervous system. In chapter 2, the X-ray crystal structure of mature, active recombinant human kallikrein 6 at 1.75 Å is presented. This high resolution model provides the first three-dimensional view of one of the human kallikreins and one of only a few structures of serine proteinases predominantly expressed in the central nervous system. Enzymatic and X-ray data provide support for the characterization of human kallikrein 6 as a degradative proteinase with structural features more similar to trypsin than the regulatory kallikreins. In chapter 3, we have re-solved the structure of hK6 to a resolution of 1.56 Å. In addition, a detailed analysis of the preferred substrate specificity of hK6 at the positions P3, P2, P1′, P2′, and P3′ is undertaken using internally quenched fluorescent substrates based on a peptide background sequence of the identified autolysis region. Furthermore, the identified optimized substrate sequence is modeled into the 1.56 Å structure of human kallikrein 6 using docking in order to identify structural aspects of the protein responsible for this preference. The substrate specificity data show that human kallikrein 6 displays little discrimination for particular amino acids at the tested positions with the exception of P2′, where there is a pronounced preference for proline. The second protein studied in this work is human fibroblast growth factor-1 which is a member of the β-trefoil superfold. In chapter 4, a 1.10 Å atomic-resolution x-ray structure of human fibroblast growth factor 1, a member of the β-trefoil superfold, is reported. The FGF-1 structure exhibits numerous core packing defects detectable using a 1.0Å radius probe. In addition to contributing to the relatively low thermal stability of FGF-1, these defects may also permit domain motions within the structure. The availability of refined ADP's permits a translation/libration/ screw (TLS) analysis of putative rigid body domains. The observed rigid body motion in FGF-1 appears related to the ligand-binding functionalities. / Dissertation / PhD

Leung Man-hin. / Thesis submitted in: August 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 119-133). / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgement --- p.iv / Abbreviations --- p.v / Figure List --- p.vii / Chapter Chapter 1: --- General introduction / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Pathogenesis of Alzheimer's disease / Chapter 1.2.1 --- Amyloid cascade hypothesis --- p.2 / Chapter 1.2.2 --- Tauopathy --- p.5 / Chapter 1.3 --- The amyloid precursor proteins / Chapter 1.3.1 --- Structure of amyloid precursor proteins and related peptides --- p.5 / Chapter 1.3.2 --- Amyloid precursor protein mutations --- p.6 / Chapter 1.3.3 --- Amyloid precursor protein processing --- p.10 / Chapter 1.3.4 --- Physiological roles of APP --- p.12 / Chapter 1.3.5 --- The pathophysiological role of Ap --- p.17 / Chapter 1.3.6 --- The pathophysiological role of APP-CTF --- p.20 / Chapter 1.4 --- The role of proteases in amyloid precursor protein processing / Chapter 1.4.1 --- α-secretase and p-secretase --- p.22 / Chapter 1.4.2 --- γ-secretase complex --- p.30 / Chapter 1.4.3 --- Caspases --- p.36 / Chapter 1.4.4 --- Kallikrein-like proteases --- p.37 / Chapter 1.5 --- Objective of the present study --- p.40 / Chapter Chapter 2: --- Materials and methods / Chapter 2.1 --- Experimental procedure / Chapter 2.1.1 --- Plasmid construction --- p.42 / Chapter 2.1.2 --- "DNA purification, ligation and restriction enzyme digestion" --- p.44 / Chapter 2.1.3 --- Competent cell preparation --- p.47 / Chapter 2.1.4 --- Transformation --- p.47 / Chapter 2.1.5 --- Plasmid miniprep --- p.48 / Chapter 2.1.6 --- Prokaryotic expression of neurosin --- p.49 / Chapter 2.1.7 --- SDS-PAGE --- p.51 / Chapter 2.1.8 --- Protein sample preparation --- p.51 / Chapter 2.1.9 --- Western Blot --- p.52 / Chapter 2.1.10 --- Immobilized metal affinity chromatography --- p.54 / Chapter 2.1.11 --- Enzyme assay --- p.55 / Chapter 2.1.12 --- Cell culture and transfection --- p.56 / Chapter 2.1.13 --- Live cell imaging --- p.57 / Chapter 2.2 --- Materials --- p.59 / Chapter Chapter 3 : --- Results / Chapter 3.1 --- Recombinant expression and characterization of neurosin / Chapter 3.1.1 --- Construction of neurosin prokaryotic expression vectors --- p.62 / Chapter 3.1.2 --- Prokaryotic expression of neurosin --- p.64 / Chapter 3.1.3 --- Neurosin was expressed as inclusion bodies --- p.68 / Chapter 3.1.4 --- Co-expression of molecular chaperones with neurosin --- p.70 / Chapter 3.1.5 --- Purification of recombinant neurosin by IMAC --- p.76 / Chapter 3.1.6 --- Enzyme assay --- p.81 / Chapter 3.2 --- Effect of neurosin on APP processing in neuronal cells / Chapter 3.2.1 --- Generation of APP constructs --- p.84 / Chapter 3.2.2 --- Expression of APP in mammalian cultures --- p.89 / Chapter 3.2.3 --- Cellular localization of APP and its processing products --- p.96 / Chapter 3.2.4 --- The role of over-expression of neurosin on APP processing in B103 cells --- p.101 / Chapter Chapter 4: --- Discussion / Chapter 4.1 --- Discussion of neurosin expression --- p.103 / Chapter 4.2 --- Discussion of APP cell model --- p.109 / Chapter 4.3 --- Conclusion --- p.119 / References --- p.121 / Appendix / Chapter A. --- Tables on primers used --- p.138 / Chapter B. --- Plasmid maps --- p.139 / Chapter C. --- Raw data on the DNA sequencing --- p.141