> I would be more worried if the blotted area was different (the dark blob)
Or if more than one blob is present (i.e. blobs at different molecular weights) for a supposedly selective and specific antibody that should show exactly one blob on the blot.
> Now, if while preparing the images they needed to do some editorial choices
Editorial choices on raw scientific data are a big no-no.
> This image is supposed to demonstrate that the antibody being sold works as intended. (…) Antibodies are near-ubiquitous but notoriously fickle laboratory reagents in biomedical research. For many applications, it is absolutely crucial that the antibodies that you use are selective (i.e., the antibody binds strongly to the target protein) and specific (i.e., the antibody binds to the protein of interest and little else).
Antibodies showing a different picture (Western blot) than what is expected can drastically change the interpretation of the results as well as the conclusion of a study, for example. It may also encourage scientific fraud by authors by forcing them to unknowingly/coincidentally make to a blot image the same (or similar) fraudulent modifications performed by the vendor.
Now I’m curious about how much of the blot photoshopping present in retracted papers can be attributed to these misleading verification data.
> that structure is as/more important than sequence?
Structure is determined by sequence, so they are equally important. Structure is more conserved than sequence, mainly due to the physicochemical constraints that govern protein folding.
> that "reaction centers" are what matter, and the rest is just "protection"?
Sometimes not even protection. Many enzymes can have plenty of its sequence/structure removed and still be functional. Natural proteins carry lots of evolutionary cruft.
> What do you mean by "reaction center" - surely not physically central within the folded structure
I think they borrowed the term from photosystems/photosynthesis. But, to be more precise, what they actually meant is the active site of an enzyme; the location where the catalyzed reaction takes place.
> (isn't it the surface shape that determines reactivity) ?
Shape is not enough, the chemical nature of the amino acid residues involved is also important. A single mutation in a key catalytic residue will shut down the enzyme even if the shape stays the same.
My PhD thesis addressed a similar question. I did a survey of sub-domain sized fragments shared between different protein folds. It turns out that there are plenty, even among folds considered evolutionarily distant.
This reminds me of structural studies in proteins encoded by de novo genes in eukaryotes. They are usually either intrinsically disordered or adopt a molten-globule-like state.
> Natural selection has no analogy with any aspect of human behavior, However, if one wanted to play with a comparision, one would have to say natural selection does not work as an engineer works. It works like a tinkerer - a tinkerer who does not know exactly what he is going to produce but uses whatever he finds around him whether it be pieces of string, fragments or wood, or old cardboards; in short it works like a tinkerer who uses everything at his disposal to produce some kind of workable object.