Biomaterial Database

Changes in site specificity of single-strand-specific endonucleases on supercoiled PM2 DNA with temperature and ionic environment. 1984

D Kowalski

Mung bean nuclease sites in supercoiled PM2 DNA at neutral pH were located by linearizing the singly-nicked circular DNA product with venom phosphodiesterase followed by restriction endonuclease mapping. The locations of the sites varied with small changes in temperature and in concentration of NaC1 or magnesium ion. Different environmental changes which affect duplex stability in the same direction showed similar effects on the number of sites and in some cases resulted in identical cleavage patterns. Venom phosphodiesterase and P1 nuclease showed cleavage patterns similar to mung bean nuclease under the same environmental conditions and showed similar variations in cleavage patterns when environmental conditions were changed. Relaxed, closed-circular DNA was slowly cleaved at numerous sites whose locations did not vary with environment. Changes in site specificity are likely the result of environmental effects on the conformation of supercoiled DNA as opposed to effects on the single-strand-specific endonucleases themselves.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D009994	Osmolar Concentration	The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.	Ionic Strength,Osmolality,Osmolarity,Concentration, Osmolar,Concentrations, Osmolar,Ionic Strengths,Osmolalities,Osmolar Concentrations,Osmolarities,Strength, Ionic,Strengths, Ionic
D011549	Pseudomonas	A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in nature. Some species are pathogenic for humans, animals, and plants.	Chryseomonas,Pseudomona,Flavimonas
D004262	DNA Restriction Enzymes	Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.	Restriction Endonucleases,DNA Restriction Enzyme,Restriction Endonuclease,Endonuclease, Restriction,Endonucleases, Restriction,Enzymes, DNA Restriction,Restriction Enzyme, DNA,Restriction Enzymes, DNA
D004277	DNA, Single-Stranded	A single chain of deoxyribonucleotides that occurs in some bacteria and viruses. It usually exists as a covalently closed circle.	Single-Stranded DNA,DNA, Single Stranded,Single Stranded DNA
D004278	DNA, Superhelical	Circular duplex DNA isolated from viruses, bacteria and mitochondria in supercoiled or supertwisted form. This superhelical DNA is endowed with free energy. During transcription, the magnitude of RNA initiation is proportional to the DNA superhelicity.	DNA, Supercoiled,DNA, Supertwisted,Supercoiled DNA,Superhelical DNA,Supertwisted DNA
D004279	DNA, Viral	Deoxyribonucleic acid that makes up the genetic material of viruses.	Viral DNA
D004720	Endonucleases	Enzymes that catalyze the hydrolysis of the internal bonds and thereby the formation of polynucleotides or oligonucleotides from ribo- or deoxyribonucleotide chains. EC 3.1.-.	Endonuclease
D001435	Bacteriophages	Viruses whose hosts are bacterial cells.	Phages,Bacteriophage,Phage