EC Number   |
Natural Substrates |
|---|
   3.5.4.B9 | cytosine in single-stranded viral DNA + H2O |
- |
| 3.5.4.B9 | deoxycytosine in single-stranded viral DNA + H2O |
- |
| 3.5.4.B9 | cytosine in single-stranded viral DNA + H2O |
cytosine deamination occurs preferentially in CpC (5'GpG/CpC5') |
| 3.5.4.B9 | 2'-deoxycytidine + H2O |
in ssDNA |
| 3.5.4.B9 | cytosine in single-stranded viral DNA + H2O |
in vitro, the enzyme has a preferred sequence motif of T/CCC and shows a 3'->5' like processivity |
| 3.5.4.B9 | cytosine in single-stranded viral DNA + H2O |
native enzyme demonstrates a preference for deamination of the C residue proximal to the 5'-ssDNA end in the 5'CCC motif and deaminates the two C residues processively |
| 3.5.4.B9 | cytosine in single-stranded viral DNA + H2O |
phage M13mp2 circular DNA containing a series of in-frame 5'-AAACCCAAA hot motifs embedded in lacZalpha reporter sequence located within a single-stranded gapped region of M13 double-stranded DNA. The third C in the 5'-AAACCCAAA motif is deaminated predominantly |
| 3.5.4.B9 | cytosine in single-stranded DNA + H2O |
the APOBEC3 enzymes are a double-edged sword that can catalyze deamination of cytosine in genomic DNA, which results in potential genomic instability due to the many mutagenic fates of uracil. The enzymes must be able to efficiently deaminate transiently available single-stranded DNA during reverse transcription, replication, or transcription. Specific biochemical characteristics promote deamination in each situation to increase enzyme efficiency through processivity, rapid enzyme cycling between substrates, or oligomerization state |
| 3.5.4.B9 | cytosine in single-stranded viral DNA + H2O |
the APOBEC3 enzymes are a double-edged sword that can catalyze deamination of cytosine in genomic DNA, which results in potential genomic instability due to the many mutagenic fates of uracil. The enzymes must be able to efficiently deaminate transiently available single-stranded DNA during reverse transcription, replication, or transcription. Specific biochemical characteristics promote deamination in each situation to increase enzyme efficiency through processivity, rapid enzyme cycling between substrates, or oligomerization state |
| 3.5.4.B9 | more |
the enzyme binds randomly to single-stranded DNA, then jumps and slides processively to deaminate target motifs. Preferential deamination of the third C is observed in the motif 5'-AAACCCAAA-3' while deamination at the first C is not observed. The replacement of AAA with TTT at the 3' side of CCC results in a 20fold inhibition of deamination. The replacement of AGA by TTT at the 5' side of CCC results in about a 5fold reduction in specific activity. Similar binding constants are observed with single-stranded DNA substrates ranging from 10 to 69 nucleotides whereas binding is reduced sharply for a 9-nucleotide substrate. When confronting partially double-stranded DNA, to which the enzyme cannot bind, sliding is lost but jumping is retained. The enzyme shows catalytic orientational specificity such that deamination occurs predominantly 3'-5' without requiring hydrolysis of a nucleotide cofactor |
