Biomaterial Database

Role of exonucleases V and VIII in adenosine 5'-triphosphate- and deoxynucleotide triphosphate-dependent strand break repair in toluenized Escherichia coli cells treated with X-rays. 1979

E A Waldstein

The repair of X-ray-induced strand breaks was studied in permeabilized Escherichia coli recBC cells deficient for the adenosine 5'-triphosphate (ATP)-dependent exonuclease V and in recBC sbcA cells that possess the ATP-independent exonuclease VIII. It is shown that repair induced by additon of ATP does not take place in recBC and recBC sbcB cells and is limited in recBC sbcA cells. ATP-dependent repair is nevertheless observable if together with ATP a mixture of deoxynucleotide monophosphates is supplied to the cells. These data fit with the assumption that in wild-type cells ATP-dependent repair involves exonuclease V-induced deoxyribonucleic acid degradation and rephosphorylation of the degradation products which are reused for deoxyribonucleic acid polymerase I-dependent break closure. Repair in the presence of deoxynucleotide triphosphates rejoins a similar fraction of breaks in all strains tested irrespective of the amount of postirradiation degradation resulting from exonuclease V and exonuclease VIII activities. Thus, exonuclease V is dispensable for deoxynucleotide triphosphate-dependent repair, i.e., does not "clean" the ends of breaks produced by X-irradiation. ATP- and deoxynucleotide triphosphate-dependent repair are not additive and seem to repair the same population of deoxyribonucleic acid molecules damaged by X-irradiation.

UI	MeSH Term	Description	Entries
D003854	Deoxyribonucleotides	A purine or pyrimidine base bonded to a DEOXYRIBOSE containing a bond to a phosphate group.	Deoxyribonucleotide
D004260	DNA Repair	The removal of DNA LESIONS and/or restoration of intact DNA strands without BASE PAIR MISMATCHES, intrastrand or interstrand crosslinks, or discontinuities in the DNA sugar-phosphate backbones.	DNA Damage Response
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D005092	Exonucleases	Enzymes that catalyze the release of mononucleotides by the hydrolysis of the terminal bond of deoxyribonucleotide or ribonucleotide chains.	Exonuclease,3'-5'-Exonuclease,3'-5'-Exonucleases,5'-3'-Exonuclease,5'-3'-Exonucleases,3' 5' Exonuclease,3' 5' Exonucleases,5' 3' Exonuclease,5' 3' Exonucleases
D000255	Adenosine Triphosphate	An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.	ATP,Adenosine Triphosphate, Calcium Salt,Adenosine Triphosphate, Chromium Salt,Adenosine Triphosphate, Magnesium Salt,Adenosine Triphosphate, Manganese Salt,Adenylpyrophosphate,CaATP,CrATP,Manganese Adenosine Triphosphate,MgATP,MnATP,ATP-MgCl2,Adenosine Triphosphate, Chromium Ammonium Salt,Adenosine Triphosphate, Magnesium Chloride,Atriphos,Chromium Adenosine Triphosphate,Cr(H2O)4 ATP,Magnesium Adenosine Triphosphate,Striadyne,ATP MgCl2
D014965	X-Rays	Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard X-rays are the higher energy, shorter wavelength X-rays. Soft x-rays or Grenz rays are less energetic and longer in wavelength. The short wavelength end of the X-ray spectrum overlaps the GAMMA RAYS wavelength range. The distinction between gamma rays and X-rays is based on their radiation source.	Grenz Ray,Grenz Rays,Roentgen Ray,Roentgen Rays,X Ray,X-Ray,Xray,Radiation, X,X-Radiation,Xrays,Ray, Grenz,Ray, Roentgen,Ray, X,Rays, Grenz,Rays, Roentgen,Rays, X,X Radiation,X Rays,X-Radiations