#drunk dimers

So, I have a few different images in my mind to explain hemoglobin binding to oxygen.

Hemoglobin is put together out of two dimers (protein structures), that are REALLY GOOD FRIENDS. They are very tight, tell each other everything, hold hands and most important, never talk to someone else. That’s their taut state.

When hemoglobin comes to the lungs, it slowly starts to see all these new people, O2. Maybe they get a little drunk one evening, and at first, it’s just the two dimers, the BFFS, out on the night together, caught up in each other. Now, as they get more tipsy, they start looking at these O2 and finally, one of the dimers decides to try out life and chat up a O2 molecule.

This of course, weakens the whole, taut state, the tight BFFS, because now dimer(a) has a new friend in her life. This is the relaxed state.

This lead to dimer(b) to ponder the rest of the soup of people (O2) and they start chatting with one as well. This obviously happens faster than it took the first dimer to start sociallizing, because lets face it, dimer(b) is now even more drunk and has just felt the distancing of her/his friend.

This then leads to dimer(a) to reach for more people (O2) or maybe the O2 that she/he was talking to just called its friend over. Anyhow, this is now fast progression of frienships formed and soon the hemoglobin is filled with its 4 O2 molecules. They now travel together towards the tissues.

Now, I need you to remember that when they lost their taut state, relaxed, they were drunk, in a bar full of O2. So naturally, they made some connections. Out here in the tissues though, there are few O2 and the dimers are sobering up quickly. The oxygen are also kind of regretting taking a ride, because they’re pretty keen on meeting some cells now, because they hear that that’s where all the fun is.

This leads to the connections loosening, until the O2 leave the hemoglobin and the dimers resume their taut state, happy to have their BFF again.