Search

De stormvloed van 1 november 2006, de Allerheiligenvloed genaamd, heeft na analyse van de waterstandsverwachting, de golfmetingen bij Schiermonnikoog Noord (SON), de veekranden en de duinafslag, geleid tot aanbevelingen voor het informatie- en kennisontwikkelingsproces. Het betreft aanbevelingen voor het instrumentarium van de SVSD, voor het inwinnen en interpreteren van gegevens en voor vervolgactiviteiten naar aanleiding van de gegevens van de Allerheiligenvloed 2006. In het volgende worden de conclusies voor het gebeurde tijdens de Allerheiligenvloed en de aanbevelingen voor het vervolg kort samengevat.

De stormvloed van 1 november 2006, de Allerheiligenvloed genaamd, heeft na analyse van de waterstandsverwachting, de golfmetingen bij Schiermonnikoog Noord (SON), de veekranden en de duinafslag, geleid tot aanbevelingen voor het informatie- en kennisontwikkelingsproces. Het betreft aanbevelingen voor het instrumentarium van de SVSD, voor het inwinnen en interpreteren van gegevens en voor vervolgactiviteiten naar aanleiding van de gegevens van de Allerheiligenvloed 2006. In het volgende worden de conclusies voor het gebeurde tijdens de Allerheiligenvloed en de aanbevelingen voor het vervolg kort samengevat.

Applied Sciences

Applied Sciences

Applied Sciences

Applied Sciences

Recombinase proteins assembled into helical filaments on DNA are believed to be the catalytic core of homologous recombination. The assembly, disassembly and dynamic rearrangements of this structure must drive the DNA strand exchange reactions of homologous recombination. The sensitivity of eukaryotic recombinase activity to reaction conditions in vitro suggests that the status of bound nucleotide cofactors is important for function and possibly for filament structure. We analyzed nucleoprotein filaments formed by the human recombinase Rad51 in a variety of conditions on double-stranded and singlestrandedDNAby scanningforce microscopy. Regular filaments with extended double-stranded DNA correlated with active in vitro recombination, possibly due to stabilizing the DNA products of these assays. Though filaments formed readily on single-stranded DNA, they were very rarely regular structures. The irregular structure of filaments on single-stranded DNA suggests that Rad51 monomers are dynamic in filaments and that regular filaments are transient. Indeed, single molecule force spectroscopy of Rad51 filament assembly and disassembly in magnetic tweezers revealed protein association and disassociation from many points along the DNA, with kinetics different from those of RecA. The dynamic rearrangements of proteins and DNA within Rad51 nucleoprotein filaments could be key events driving strand exchange in homologous recombination., Kavli Institute of Nanoscience Delft, Applied Sciences

Recombinase proteins assembled into helical filaments on DNA are believed to be the catalytic core of homologous recombination. The assembly, disassembly and dynamic rearrangements of this structure must drive the DNA strand exchange reactions of homologous recombination. The sensitivity of eukaryotic recombinase activity to reaction conditions in vitro suggests that the status of bound nucleotide cofactors is important for function and possibly for filament structure. We analyzed nucleoprotein filaments formed by the human recombinase Rad51 in a variety of conditions on double-stranded and singlestrandedDNAby scanningforce microscopy. Regular filaments with extended double-stranded DNA correlated with active in vitro recombination, possibly due to stabilizing the DNA products of these assays. Though filaments formed readily on single-stranded DNA, they were very rarely regular structures. The irregular structure of filaments on single-stranded DNA suggests that Rad51 monomers are dynamic in filaments and that regular filaments are transient. Indeed, single molecule force spectroscopy of Rad51 filament assembly and disassembly in magnetic tweezers revealed protein association and disassociation from many points along the DNA, with kinetics different from those of RecA. The dynamic rearrangements of proteins and DNA within Rad51 nucleoprotein filaments could be key events driving strand exchange in homologous recombination., Kavli Institute of Nanoscience Delft, Applied Sciences