Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.64 (proteinase K)
 4,071 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The sedimentation of L1210 nucleoids has been used to demonstrate a hyperthermia-associated increased protein to DNA ratio and an apparent inhibition of processes involved in the restoration of the protein to DNA ratio. The distance of nucleoid sedimentation increased as a function of exposure temperature and exposure time, and was proportional to an increased protein to DNA ratio in the nucleoids. Studies in which control and hyperthermia-treated cells were mixed prior to nucleoid preparation indicated that the association of protein with the nucleoid occurred during hyperthermia treatment and not during nucleoid preparation. However, double-labelling studies suggested an interaction between control and hyperthermia-treated cells since the presence of control cells during lysis resulted in near normalization of nucleoid sedimentation. Treatment with proteinase K also restored the nucleoid sedimentation. Incubation at 37 degrees C following hyperthermia revealed a rapid restoration of nucleoid sedimentation and a slower restoration of the protein to DNA ratio. Ethidium bromide-induced changes in nucleoid sedimentation were altered by the hyperthermia-associated increased protein content of nucleoids and the alterations were overcome by enzymatic digestion of the protein prior to the ethidium bromide exposure. Thus, hyperthermia caused, and inhibited the repair of, an increased protein content of nucleoids. The restoration of the increased protein possibly occurs by a heat-sensitive proteolytic enzyme. The temporal use of an appropriate chemotherapy agent to inhibit the restoration of hyperthermia-associated changes may be a useful treatment option.
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PMID:Restoration of hyperthermia-associated increased protein to DNA ratio of nucleoids. 355 98

Intact and fast-sedimenting nucleoids of Bacillus licheniformis were isolated under low-salt conditions and without addition of detergents, polyamines or Mg2+. These nucleoids were partially unfolded by treatment with RNase and completely unfolded by treatments that disrupt protein-DNA interactions, like incubation with proteinase K, 0.1% sodium dodecyl sulphate and high ionic strength. Ethidium bromide intercalation studies on RNase-treated, proteinase-K-treated and non-treated nucleoids in combination with sedimentation analysis of DNase-I-treated nucleoids revealed that DNA is organized in independent, negatively supertwisted domains. In contrast to the DNA organization in bacterial nucleoids, isolated under high-salt conditions and in the presence of detergents (Stonington & Pettijohn, 1971; Worcel & Burgi, 1972), the domains of supertwisted DNA in the low-salt-isolated nucleoids studied here are restrained by protein-DNA interactions. A major role for nascent RNA in restraining supertwisted DNA was not observed. The superhelix density of B. licheniformis nucleoids calculated from the change of the sedimentation coefficient upon ethidium bromide intercalation, was of the same order of magnitude as that of other bacterial nucleoids and eukaryotic chromosomes, isolated under high-salt conditions: namely, -0.150 (corrected to standard conditions: 0.2 M-NaCl, 37 degrees C; Bauer, 1978). Electron microscopy of spread nucleoids showed relaxed DNA and regions of condensed DNA. Spreading in the presence of 100 micrograms ethidium bromide per ml revealed only condensed structures, indicating that nucleoids are intact. From spreadings of proteinase-K-treated nucleoids we infer that supertwisted DNA and the protein-DNA interactions, responsible for restraining the superhelical DNA conformation, are localized in the regions of condensed DNA.
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PMID:Folding of prokaryotic DNA. Isolation and characterization of nucleoids from Bacillus licheniformis. 618 37