a Proposal for the attachment of Water to Guanine
In 1953 Watson and Crick proposed a double helix structure for DNA, having doubts about the then proposed triple helix. That proposal has now become the accepted model.
Since then the sequence of events which lead from damage of DNA to mutation has not been fully understood. There remains a change to the guanine molecule at C8 which appears to require more energy than is available.
In an effort to find a source of this energy, researchers have proposed that the presence of a sodium counter-ion in the vicinity of an electron "hole" in the guanine, caused by oxidative damage, provides the energy necessary to initiate the attachment of a water molecule to that hole. That proposal suggests that an oxygen with one of it's hydrogens attaches at C8 with the other hydrogen transferring to an adjacent water molecule. The partner water molecule thus becomes an hydronium to bond with an adjacent phosphate to complete the change to the guanine. However, the probability of these events occurring spontaneously and concurrently is too high and does not correlate in any way with the observed increase in cancers over the past 60 years. Also, animal studies have suggested that phosphate buffer pairs mitigate the over-production of reducing agents in the presence of oxidising free radicals and this seems contrary to the notion of a phosphate facilitating mutation.
I propose that a more probable mechanism involves an hydronium rather than a sodium cation. I further propose that the hydronium has an altered valency as a result of passing through electrically live water piping.
The mutation begins with an oxidising free radical scavenging an electron from DNA. The electron "hole" may migrate along the DNA until it reaches a guanine, where no further reaction can take place as the guanine has the lowest attachment bonding to it's electrons, or it may occur at the guanine itself.
In this proposed mechanism, the hydronium involved in forming an OH on the damaged guanine at C8 is not short lived. The hydronium starts as a long lived cation which is energised by the negative half wave of alternating current and can be regarded as behaving like an anion. It is in a larger form of hydronium molecule structure rather than a simple H3O. The hydrated proton resides on the surface of this molecule rather than being within a cage. In this surface location on the molecule the hydronium can bond with guanine at the electron hole. The process is completed when the oxidising free radical which began the process, but which now has it's electron, is bonded to that part of the now de-energised hydronium structure remaining after an OH component has been bonded to the guanine at C8. Thus the proposed process completes in the presence of two molecules, being the oxidising free radical and the energised hydronium, and requires no catalysts for the reaction to complete.
This proposal must be regarded as unproved, but offers a possible epidemiologically based explanation to the change to guanine at C8.
firstname.lastname@example.org Stephen Butcher (B. Arch, Dip.BS)
Stephen G Butcher (Revised into html from pdf 16/03/13)