Spelling suggestions: "subject:"asurface display"" "subject:"asurface isplay""
21 |
Bacterial Display of a Tau-Binding Affibody Construct:Towards Affinity MaturationEk, Moira January 2020 (has links)
Aggregation of microtubule-associated protein tau is involved in the pathology of several neurodegenerative diseases, including Alzheimer’s disease. The affibody TP4 has been shown to inhibit this aggregation process, and its target-binding positions were previously grafted onto a dimeric affibody scaffold, creating the sequestrin seqTP4. This project constitutes a part of the affinity maturation process of seqTP4, using two different bacterial display methods. An error-prone PCR library was first expressed on Staphylococcus carnosus cells for selection of variants with improved tau-binding properties, resulting in a library of 1.4×107 transformants. Flow cytometric tests indicated difficulties in the setup due to nonspecific interactions, and whereas several different approaches to alleviate the problems were investigated, two cell sorting attempts were ultimately unsuccessful. Subcloning of seqTP4 and the library to an Escherichia coli surface display vector resulted in functional surface expression of seqTP4 on E. coli JK321 and BL21 cells, and a BL21 library size of 1.6×109 transformants. An initial flow cytometric test of this library indicates the presence of improved tau-binding variants, paving the way for future cell sorting. / Aggregering av mikrotubuli-associerat protein tau är involverad i patologin av flera neurodegenerativa sjukdomar, däribland Alzheimers sjukdom. Affibodymolekylen TP4 har visat sig inhibera denna aggregeringsprocess, och överföring av dess målbindande positioner till ett dimeriskt affibodyprotein har tidigare gett upphov till seqTP4, en så kallad sequestrin. Detta projekt utgör ett led i processen att affinitetsmaturera seqTP4, med hjälp av två olika metoder för presentation av proteiner på ytan av bakterieceller. Ett error-prone PCR-bibliotek uttrycktes först på ytan av Staphylococcus carnosus-celler för selektion av varianter med ökad affinitet för tau, vilket resulterade i ett bibliotek av 1.4×107 transformanter. Flödescytometriska tester tydde på svårigheter i detta upplägg på grund av ospecifika interaktioner, och emedan flera olika angreppssätt för att förmildra dessa problem undersöktes, misslyckades slutligen två cellsorteringsförsök. Omkloning av seqTP4 och biblioteket till en vektor för ytpresentation på Escherichia coli resulterade i funktionellt ytuttryck av seqTP4 på E. coli JK321- och BL21-celler, och ett BL21-bibliotek bestående av 1.6×109 transformanter. Ett första flödescytometriskt test av detta bibliotek tyder på närvaron av varianter med förbättrad förmåga att binda tau, och vägen ligger nu relativt öppen för cellsortering.
|
22 |
Neue Zugänge zu enantioselektiven lipolytischen Enzymen durch fluoreszenzbasierte Durchmusterung kombinatorischer Bibliotheken / Novel approaches to enantioselective lipolytic enzymes via fluorescence based screening of combinatorial librariesBecker, Stefan 31 October 2007 (has links)
No description available.
|
23 |
Funktionelle Charakterisierung potentieller Pathogenitätsfaktoren aus Pseudomonas aeruginosa mittels biochemischer und evolutiver Methoden / functional characterization of potential pathogenicity factors from Pseudomonas aeruginosa by biochemical and evolutionary methodsAdams, Thorsten 27 January 2005 (has links)
No description available.
|
24 |
Exposition von Proteinen auf der Oberfläche von Escherichia coli Zellen: mechanistische Betrachtung und biotechnologische Anwendung / Exposition of proteins on the surface of Escherichia coli cells: mechanistic consideration and biotechnological applicationWentzel, Alexander 07 May 2003 (has links)
No description available.
|
25 |
Identification and characterization of gallium-binding peptidesSchönberger, Nora 23 April 2021 (has links)
The present work demonstrates how a peptide-based material can be obtained for the biosorptive recovery of metals from contaminated industrial wastewater. Starting with Phage surface display for the initial identification and optimization of gallium-binding peptides, all the following application-focussed experiments are based on chemically synthesized peptides.
Two chromatography-based biopanning methods for the identification of gallium-binding peptides from a commercial phage display library were developed. Five gallium-binding peptide sequences were identified and evaluated to show good gallium-binding properties.
Furthermore, the biosorption of free gallium and arsenic by gallium-binding bacteriophage clones was investigated. A large influence of the pH-value on the respective interactions was demonstrated.
Mutagenesis experiments were also carried out for a bacteriophage clone expressed peptide, in which a cysteine pair systematically replaced amino acids. Biosorption experiments with the resulting seven different bacteriophage mutants suggested a relationship between the rigidity of the peptide structure and the gallium-binding properties.
In isothermal titration experiments, the thermodynamics of the interaction between gallium and the peptides as chemically synthesized derivatives were characterized, independent of the bacteriophage. The peptides differed strongly in their interaction with gallium, and in some cases, the complex formation with gallium depended strongly on the surrounding buffer conditions.
The peptide with the amino acid sequence NYLPHQSSSPSR has particularly promising gallium-binding properties. Computer modeling suggests the probable structure of the peptide in aqueous solution and postulates a possible binding site for gallium.
The side-selective and covalent immobilization of the peptides on a polystyrene matrix led to the creation of a biocomposite for the biosorptive recovery of gallium. The sorption performance and desorbability of the peptide-based biosorption materials were determined in studies with model solutions and real waters from the semiconductor industry.
:EIDESSTATTLICHE VERSICHERUNG II
SUMMARY 7
CHAPTER I. 8
Utility of biotechnological approaches in resource technology 9
Phage Surface Display for the recovery of inorganic binding peptides 14
Gallium – Example of a high-tech metal 22
Aims and context of the present work 22
CHAPTER II. 25
Author contributions 25
Abstract 25
Introduction 26
Materials and Methods 28
2.1 Phage Display Library system 28
2.2 Biopanning experiments 29
2.3 Single clone identification 31
2.4 Single clone binding studies 31
Results 32
3.1 Immobilization of gallium ions 32
3.2 Biopanning experiments 33
3.3 Single clone binding studies 38
Discussion 39
4.1 Gallium ions as biopanning target 39
4.2 Phage clone selection 40
Conclusion 44
Acknowledgements 45
CHAPTER III. 46
Author contributions 46
Abstract 47
Introduction 47
Materials and Methods 49
2.1 Handling of phage display library clones 49
2.2 Site-directed mutagenesis experiments 50
2.3 Biosorption experiments 51
Results and Discussion 52
3.1 Experimental context 52
3.2 Original phage clone characterization 53
3.3 Site-directed mutagenesis experiments 56
3.4 Mutant phage clone characterization 57
Conclusions 59
Acknowledgements 60
CHAPTER IV. 61
Author contributions 61
Textual and graphical abstract 62
Introduction 63
Methods 65
2.1 Peptides 65
2.2 Isothermal titration microcalorimetry (ITC) 65
2.3 Preparation of peptide conjugates 65
2.4 Biosorption studies 66
2.5 Model calculation of peptide C3.8 67
Results and Discussion 68
3.1 Interaction studies of free peptides in solution 68
3.2 Biosorption studies with peptide polystyrene conjugates 71
3.2.1 Covalent and site-selective immobilization of peptides 71
3.2.2 Interaction of peptide conjugates with gallium 72
3.2.3 Interaction of peptide conjugates with arsenic 73
3.2.4 Continuous experiments 73
3.3 Model calculation for peptide C3.15 75
Counclusion 76
Acknowledgment 77
CHAPTER V. 78
Obtained insights for the selection of metal-binding peptides in biopanning experiments 79
Conclusions for the development of peptide-based materials for the biosorptive recovery of metal ions from aqueous solutions 81
REFERENCES 85
APPENDIX 94
SUPPORTING INFORMATION FOR CHAPTER IV 94
LIST OF FIGURES 99
LIST OF TABLES 100
LIST OF ABBREVIATIONS 101
LIST OF CHEMICALS 104
ACKNOWLEDGEMENTS 106
CURRICULUM VITAE 109
LIST OF PUBLICATIONS 111
|
Page generated in 0.0399 seconds