digestion results in about 25 fragments that migrate as discrete bands on polyacrylamide gel. These bands give unique fingerprints, indicating that the enzyme has considerable specificity
DNA where cytosine is partially or completely replaced by hydroxymethylcytosine + H2O
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Tequatrovirus T4
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DNA where cytosine is partially or completely replaced by hydroxymethylcytosine is degraded in vivo by T4 endonuclease II, EC 3.1.21.8, and endonuclease IV, EC 3.1.21.9
the phage T4 enzyme is involved in degradation of host DNA. It introduces breaks preferentially into single stranded DNA. It produces oligonucleotides as small as 150 nucleotides long from fd DNA. These oligonucleotides contain 3'-hydroxyl and 5'-phosphate termini. T4 endonuclease IV produces breaks exclusively adjacent to cytosine residues in both fd and denatured lambda DNA.The enzyme does not cleave double-stranded DNA or native T4 DNA, which contains 5-hydroxymethylcytosine instead of cytosine
enzyme is capable of cleaving at the atypical apurinic-apyrimidinic site created by the action of T4 PD-DNA glycosylase. Exonuclease III and endonuclease IV are equally efficient in repair
enzyme displays about 200fold greater activity toward single stranded DNA than toward duplex DNA. The limit product obtained by exhaustive digestion of single stranded DNA with endonuclease IV is 25% acid-soluble and consists of oligonucleotides with an average chain length of about 50 nucleotides. Enzyme does not display exonuclease activity. No substrate: denatured bacteriophage T4 DNA
enzyme shows high activity with single-stranded DNA and denatured dC-substituted T4 genomic double-stranded DNA but exhibits no activity with dsDNA, ssRNA or denatured T4 genomic dsDNA containing glucosylated deoxyhydroxymethylcytidine. Endo IV catalyzes specific endonucleolytic cleavage of the 5' phosphodiester bond of dC in ssDNA with an efficiency markedly dependent on the surrounding nucleotide sequence. The enzyme preferentially targets 5'-dTdCdA-3' but tolerates various combinations of individual nucleotides flanking this trinucleotide sequence
in single-stranded DNAs from bacteriophages PhiX174, fd, M 13, 74-82% of the 5'-terminal dinucleotides obtained after cleavage end in 5'-deoxycytidylic acid. Small but significant levels of several dinucleotides ending in 5'-deoxyadenylic acid, 5'-thymidylic acid and 5'-deoxyguanylic acid are also found. All 3'-terminal nucleotides are present with a large predominance of thymidylic acid
DNA where cytosine is partially or completely replaced by hydroxymethylcytosine + H2O
?
Tequatrovirus T4
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DNA where cytosine is partially or completely replaced by hydroxymethylcytosine is degraded in vivo by T4 endonuclease II, EC 3.1.21.8, and endonuclease IV, EC 3.1.21.9
enzyme is capable of cleaving at the atypical apurinic-apyrimidinic site created by the action of T4 PD-DNA glycosylase. Exonuclease III and endonuclease IV are equally efficient in repair
CoCl2 can substitute for MgCl2. The activity at the optimal Co2+ concentration (0.001 M) is 27% higher than that found at the optimal Mg2+ concentration
the absence of either exonuclease III or endonuclease IV has no effect on survival. Exonuclease III and endonuclease IV are equally able to repair the apurinic-apyrimidinic site created by PD-DNA glycosylase. This apurinic-apyrimidinic site is atypical, since only the 5' glycosyl bond in the dimer is cleaved and the product is a cyclobutane dimer bound to DNA by a single glycosyl bond. Neither T4 endonuclease V nor endonuclease III is required for the repair of these apurinic-apyrimidinic sites
Biochemical analysis of the substrate specificity and sequence preference of endonuclease IV from bacteriophage T4, a dC-specific endonuclease implicated in restriction of dC-substituted T4 DNA synthesis
Bacteriophage T4 endonucleases II and IV, oppositely affected by dCMP hydroxymethylase activity, have different roles in the degradation and in the RNA polymerase-dependent replication of T4 cytosine-containing DNA