And yet that basically forms the basis for the adaptive immune system. First the initial VDJ recombination, followed by recurring rounds of random mutation of a protein, such that it forms a well-fitting interface that can bind another. From a stage where the first iteration of binding Ig’s might be relatively weak and imprecise.
Oh and also, I recalled Art Hunt wrote something about that a mere 13 years ago: On the evolution of Irreducible Complexity
The bottom line is that T-urf13 is a new protein, encoded by a gene that has no protein-coding antecedents; it is, bluntly, a new protein that arose “from scratch”, through a series of duplications, recombinations, and other mutations that occurred spontaneously in the course of the breeding process that gave rise to the cmsT line.
These points are already problematic for the assertion by ID proponents that new protein-coding information cannot arise by natural processes. But T-urf13 is more than a nondescript polypeptide that happens to affect male fertility in corn. It turns out that T-urf13 is a membrane protein, and in membranes it forms oligomeric structures (I am not sure if the stoichiometries have been firmly established, but that it is oligomeric is not in question). This is the first biochemical trait I would ask readers to file away – this protein is capable of protein-protein interactions, between like subunits. This means that the T-urf13 polypeptide must possess interfaces that mediate protein-protein interactions. (Readers may recall Behe and Snokes, who argued that such interfaces are very unlikely to occur by chance.)
T-urf13 also binds to the toxin produced by the fungal pathogen. But it does not just bind the toxin “passively” – upon binding, a non-selective ion channel is opened, leading to dissipation of transmembrane ion gradients, and all of the resulting events that accompany collapse of proton-motive force. (In mitochondria, this will lead to uncoupling and crippling of mitochondrial function; this is probably why cmsT plants are so devastated by the disease.) This is the second biochemical trait that readers should keep fresh in their minds – T-urf13 is a gated ion channel. (This an the other interesting biochemical properties of Turf13 are reviewed in reference 7.)