Dokument: Interaction, recognition, and condensation of DNA duplexes
| Titel: | Interaction, recognition, and condensation of DNA duplexes | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=2298 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20021125-000298-6 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Cherstvy, Andrey [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Löwen, Hartmut [Gutachter] Prof. Dr. Kornyshev, Alexej [Gutachter] | |||||||
| Stichwörter: | DNS Duplex, DNS-DNS Wechselwirkung,abgeschirmte Coulomb-Wechselwirkung, DNA Erkennung, Gentherapy, DNS-DNSElectrostatik in Salzloesungen, Lineare und Nichtliniare Poisson-BoltzmannGleichung, DNS Condensation, Adsorption, DNS Torsionselastizitaet,TorsionsDefekten in DNSHelical Strukture. Theory of electrostaticinteraction of DNA duplexes, DNA condensation, DNA helical symmetry,temperature-induced DNA condensation, adsorption of cations on DNAsurface, DNA-DNA recognition, homologous recombination and gene shuffling,DNA homologous duplexes, DNA torsional rigidity, patterns of DNA twistangles. | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 530 Physik | |||||||
| Beschreibung: | The helical symmetry of DNA plays the key role in many cell processes.
This symmetry is also of the paramount importance for description of many
DNA properties observed in vitro. In the first part we give an
explanation of one such phenomenon: temperature-induced DNA condensation
in the presence of Mn2+, detected by osmotic stress measurements in dense
columnar hexagonal DNA assembly. Our analysis is based on the theory of
electrostatic interaction of ideal DNA duplexes developed by
A.A.Kornyshev and S.Leikin several years ago. We have modified this
theory to take into account the non-fixed, self-consistently determined,
distribution of adsorbed cations on DNA surfaces. DNAs thus adopt the
patterns of adsorbed cations to minimize the total free energy. With
temperature increase and with compression of the aggregate cations occupy
the major DNA groove that stimulates attraction between DNAs due to
better charge separation along the helices. When DNAs are pushed
together, the entropy of the aggregate increases due to higher binding
entropy of cations in the major groove. For plausible model parameters
both the calculated force curve and entropy change agree quantitatively
with experimental data. It confirms the hypothesis that in dense
assemblies DNAs interact predominantly electrostatically. In the second part we explore the basic consequences of electrostatic interaction of non-ideally helical DNA duplexes of a finite torsional rigidity. We generalize the theory of interaction of ideal duplexes for the case of non-rigid DNA molecules with sequence-dependent twist patterns. It is shown that the interaction energies of rigid homologous and non-homologous DNA sequences differ dramatically: the latter cannot attract. Non-rigid DNAs with random base-pair sequences adjust their incommensurate twist patterns, soft enough sequences can profit from restored strand-groove alignment and attract each other. The recognition energy of homologous sequences increases linearly with their le! ngth, similarly to the frequency of recombination between homologous DNA fragments in many organisms. It suggests that electrostatic interaction of juxtaposed intact duplexes of 100-200bp-long can be responsible for their recognition from a distance. We have determined the set of parameters which can affect the recognition energy. It gives a hint to control homologous recombination. Experimental verification of the predicted tendencies could help understanding how homologous DNA sequences recognize each other in gene shuffling reaction and DNA repair, the (most) important phenomena for existence and evolution of life. | |||||||
| Lizenz: |  Urheberrechtsschutz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Physik | |||||||
| Dokument erstellt am: | 25.11.2002 | |||||||
| Dateien geändert am: | 12.02.2007 | |||||||
| Promotionsantrag am: | 25.11.2002 | |||||||
| Datum der Promotion: | 25.11.2002 |
