An in vitro system for studying DNA demethylation has been established using extracts from tissue culture cells. This reaction, which is unusually resistant to proteinase K, takes place through the removal of a 5-methylcytosine nucleotide unit from the DNA substrate and its conversion to an RNase-sensitive form. It is likely that this represents the in vivo mechanism, as well, since extracts fr...

Using the UHV experimental endstation on the soft X-ray beamline at the Australian Synchrotron, lysozyme and proteinase K crystals have been exposed to a vacuum of 10-5 mbar, prior to flash-cooling in a bath of liquid nitrogen. Subsequent data collection on the MX2 beamline at the Australian Synchrotron demonstrated that, for lysozyme and proteinase K, it is possible to subject these mounted cr...

Proteins are dynamic entities in cellular solution with functions governed essentially by their dynamic personalities. We review several dynamics studies on serine protease proteinase K and HIV-1 gp120 envelope glycoprotein to demonstrate the importance of investigating the dynamic behaviors and molecular motions for a complete understanding of their structure-function relationships. Using comp...

Department of Medical Microbiology, University of Z/irich, 8028 Z/irich, Switzerland A large number of different protocols for the efficient isolation of highly purified DNA from eukaryotic and prokaryotic cells is extant. (1-4) These procedures usually include treatment with proteinase K in the presence of SDS, which efficiently lyses the cells and nuclei and liberates the DNA tightly bound in...

AIM To establish a nutrient-stressed multispecies model biofilm and investigate the dynamics of biofilm killing and disruption by 1% trypsin and 1% proteinase K with or without ultrasonic activation. METHODOLOGY Nutrient-stressed biofilms (Propionibacterium acnes, Staphylococcus epidermidis, Actinomyces radicidentis, Streptococcus mitis and Enterococcus faecalis OMGS 3202) were grown on hydro...