Mission impossible in the McsB factory: Convincing a poor molecule to share its precious electrons for making something great (not again).
Overall, this picture should illustrate a novel enzyme “factory” - thus the indicated wheels pointing to a “molecular machine”.
For non-chemists, the reaction promoted by the enzyme of interest (named McsB) is chemically very challenging, and as I sometime try to explain to students, comparable with a social/human task to convince someone having little money to give further money away.
In the molecular world, the moiety (person) sharing its electrons (money), is shown on the left side, with an overlaid chemical formula representing an arginine amino acid. The arginine is connected to a protein body, somehow indicated by the open shape on the left side (compared to the shown arginine, this part is much bigger).
The moiety accepting the electrons (money) is shown on the right side, which is an ATP molecule (actually a very rich one) with its overall shape and its chemical formula indicated.
What the enzyme factory now does, is a kind of mediator/negotiator job. The little guys shown, push/transfer electrons (these heaps and stones) towards the poor arginine to make its loss easier, whereas the other guys on the right side pull/carry electrons away from the rich molecule, the ATP. So, it’s a pushing of electrons/stones on the left, and a pulling on the right, achieved by these little doozers (as in the Fraggles). In sum, it’s a pretty busy job, requiring a tight coordination of a few “coordinating” guys, holding the poor and rich chemical groups. In fact, these “aligning” doozers are among the most critical ones.
In making this figure, I was thinking of a comic-like presentation, trying to show the highly coordinated (in fact pretty complicated) activity of the many workers in the enzyme factory in an easily accessible way. Not an easy task, in fact.