Minor tautomer mismatches
The minor differences tautomers, the overall shape, Watson – almost complete imitation Crick base pairs, they do not have any atom hydrogen bonded same secondary channel and Lord.
There is a metal binding ligand that may exist in tautomeric structure different significantly changing the tautomeric equilibrium by stabilizing small, often individual tautomers. Metal complexes of the minor tautomer is often wrong assumption that it is independent of the chemical of low concentrations and its very misleading. In fact, the X-ray structure data available through nucleobase of the metal complex, the binding of the rare earth metals, that in contrast to the preferred tautomers, it is exceptional way is clear. Watson – Through the metal coordination, such as the potential mutagenicity, and “the promotion of rare tautomers”, in the case of nucleotide bases, deviation from Crick base pairs, particularly for biodiversity is important.
In recent years, including X-ray crystallography, a reference to “stabilize rare earth metal base tautomers” is defined for all of the nucleobases of the DNA in general. Metal binding caused a small structural changes relatively nucleotide bases, and acids – for example, an electronic change represented by the basic properties may be important. In addition, changes in acid nucleobases forming base mismatch with the metal surface – to prevent pairing, members of the biological effects of occupation of nucleobase portion having the chemical nature of the base to the acid in a nucleic acid – base catalyst I’m considering the action. Is not related to the biological behavior of the unsubstituted parent nucleobase, the lighting in this regard, and therefore is included.
T9 base pairs, and the structure of the binding Holiday is not a direct cause to tautomerism of thymine approximate Sheikh · A2. The car 1, A2 · T9 base pair is a two-step from the cross junction might expect that the most embarrassing structure. Furthermore, it is a T base pair at the position corresponding to the hand base pairs four of the asymmetric unit therein, Watson standard – to form Crick base pairs. Furthermore, it is not in contact A2 · T9 position opposite S3 S4 · shoulder junction. Finally, the G base pair wobbling local or · C · T in that way, the crystal structure of previous symmetric bonding has been reported. The in this way, rather than the node to make shake base pairs, it is · G will be crystallized, DNA is tested with DNA of B-type standard as a double C Standard types in this region of the base pairs adjacent intersections that function as a means that can be also be readily apparent, for the G · C rich sequences is clearly in favor of a DNA duplex, does not correspond to the type spiral.
As a result of the adoption of tautomeric type base (thymine presumably) rare highly B-DNA, the · T base pair, the model consists of all C · G · these sequences to be upset I shows that. As mismatched base pairs, duplicating machine, so to recognize a wobble related, tautomerism, such would be mutagenic very. Or enol – adenine or Iminochimin causes a transition from · T mutation in one of the mutations most common for replication, G · C base pairs, was observed in nature. This is compared to the rate of uptake of miss-T, · C-IIA-dependent incorporation of a nucleotide sequence associated with the miss incorporation at higher poly G and column primer or template (A / T) poly It is strongly dependent sequence for C, that there is shown is shown.
Dramatic sequence context dependence of these mistakes contamination was due to base stacking effect of DNA ends before, but it can occur from the sequence effect on tautomeric preferences of the template nucleotide or incoming. Show that it is possible rare tautomers is housed in a complex replication crystal structure stearothermophilus high quality DNA polymerase a rare earth tautomeric protonated cytosine pairs with mutagenic O6-methyl guanine bases B. shows. Our results, “Rare original that can occur from misincorporating polymerase nucleotides are stirred hydrogen bonds frequent pattern mutation of a gene associated with the base tautomers due to DNA sequence This indicates that it is possible nucleotide tautomers rare tautomers “hypothesis, stabilize the lending credibility. In this case, as seen in the replication complex, enol it is possible or proposed a poly G-poly-C sequence within the B-duplex DNA, thereby contributing to relatively common – is adenine or thymine – The occurrence of a transition mutation in this sequence context · T · G base pair C, which help to stabilize the imino tautomer.
Implication Another interesting of this structure is induced to loose T configuration is stabilized by an array in this intersection, in the … In particular, it is a base pair of strong shear. The T9 wobble base pairs, or tautomer, the thymine base enol rare, probably less, stabilization sequence effect is due to the imino tautomer of adenine in double of B-DNA structure of this-A2 the possible offers. , Located on the edge of the adjacent C · G base pair (FAS / GGGG) one 4, T wobble is a crystal structure of B-type helix about this sequence motif it. Observation ends of Poly C · Poly G that is sheared been shown to induce such disorders related to B-helix base pairs very base pairs C7 · G4 at the other end of this section.
Indicates that the sequence motif has the structural features unique thereof · G base pairs, particularly susceptible to deamidation bisulfite. Sequence stretch and consecutive long of the C · G is willing to accept the alternative structure. That the sequence of previous D (CCGGGCCCGG) is of the form or crystallize the intersection or double has been shown that we, the four-stranded complex, accept the B-type structure all arms. Thus, typically, binding sequence to form a double helix A-DNA appears to to allow it may be considered as B-type double helix, which is similar to the conformation of the DNA protein complex.