| dc.contributor.advisor | Griesinger, Christian Prof. Dr. | |
| dc.contributor.author | Carneiro, Marta | |
| dc.date.accessioned | 2016-01-26T10:34:50Z | |
| dc.date.available | 2016-01-26T10:34:50Z | |
| dc.date.issued | 2016-01-26 | |
| dc.identifier.uri | http://hdl.handle.net/11858/00-1735-0000-0028-86A9-F | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-5486 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-5486 | |
| dc.language.iso | eng | de |
| dc.relation.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | |
| dc.subject.ddc | 571.4 | de |
| dc.title | Functional dynamics of the anti-HIV lectin OAA and NMR methodology for the study of protein dynamics | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Enderlein, Jörg Prof. Dr. | |
| dc.date.examination | 2015-11-18 | |
| dc.description.abstracteng | Specific recognition between biomolecules is at the basis of all biological
processes, and a mechanistic description of molecular recognition is crucial for a detailed
understanding of these processes. Two limiting models are currently discussed in the
context of molecular recognition: (i) induced-fit, which postulates that conformational
changes between free and bound states are the result of the binding interaction and (ii)
conformational selection, according to which the binding interaction selects one of the
multiple conformers that pre-exist in equilibrium in the absence of binding partner. A
necessary (but not sufficient) condition to demonstrate a conformational selection scenario
is the characterization of conformational substates in the absence of binding partner
comparable to the conformations seen for the bound forms. NMR spectroscopy is a
powerful technique for studying conformational heterogeneity in solution, given its
sensitivity to a broad range of motional timescales in solution with atomic resolution.
The first part of this thesis is dedicated to the study of functional dynamics of the
lectin OAA, aimed at the elucidation of the molecular recognition mechanism underlying
its anti-HIV activity, which stems from binding to high-mannose glycans on the viral
envelope glycoproteins. Previously determined X-ray crystallography structures identified
a distinct conformational change between the free and sugar-bound protein. By using a
variety of NMR methods we show that both sugar-free and sugar-bound conformations are
conformational substates of the free protein. Further, our results indicate that the sugarbound
conformation is highly populated even in the absence of sugar, suggesting that
recognition of high-mannose glycans by OAA proceeds by conformational selection within
the ground state. These insights may guide further optimization and/or development of
preventive anti-HIV therapeutics.
The second part of the thesis is concerned with the development of new strategies
aimed at extending the efficacy and accuracy of two NMR methods frequently used to
investigate lowly populated conformational states. We show that the demanding
experimental time required by exchange-mediated saturation transfer experiments can be
reduced by two-fold by making use of Fourier transform and linear prediction. We also
demonstrate that the simultaneous analysis of data collected with at least two radiofrequency
field strengths is necessary for extracting reliable exchange parameters from these experiments. Additionally, we present a method for the identification of dynamic
clusters based on model selection using the Akaike information criterion. The efficiency of
the method is discussed in the context of synthetic CPMG relaxation dispersion data, but
the principles outlined here can be easily applied on the analysis of a variety of
experiments. | de |
| dc.contributor.coReferee | Grüne, Tim Dr. | |
| dc.contributor.thirdReferee | Tittmann, Kai Prof. Dr. | |
| dc.contributor.thirdReferee | Zweckstetter, Markus Prof. Dr. | |
| dc.contributor.thirdReferee | Groot, Bert De Prof. Dr. | |
| dc.subject.eng | NMR | de |
| dc.subject.eng | Structural Biology | de |
| dc.subject.eng | Conformational Selection | de |
| dc.subject.eng | Anti-HIV lectin | de |
| dc.subject.eng | OAA | de |
| dc.subject.eng | Oscillatoria agardhii agglutinin | de |
| dc.subject.eng | Molecular Recognition | de |
| dc.subject.eng | Protein dynamics | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-11858/00-1735-0000-0028-86A9-F-7 | |
| dc.affiliation.institute | Göttinger Graduiertenschule für Neurowissenschaften, Biophysik und molekulare Biowissenschaften (GGNB) | de |
| dc.subject.gokfull | Biologie (PPN619462639) | de |
| dc.identifier.ppn | 846555123 | |