Donahue corrects base-pair structures

1:06:00tinker around." >> Mhm. They get these models of um nucleotides, those base pairs that I was showing you earlier, and they start trying to put them together in the way that they know now, right? Things have to be antiparallel. The phosphates have to be on the outside. The nitrogenous bases have to be on the inside. It's still not quite working until their office mate Jerry Donahghue looks at the bases that they're the the Lego blocks that they're using to like do this and he's like actually um you're doing it wrong. The given the pH of the cell and the temperature of of living organisms, the the hydrogen there isn't actually

1:06:41going to be there. It's going to be over here. >> Mhm. >> And Mhm. >> Watson's like, "Oh, okay." [laughter] And then he goes back to the machine shop. He's like, "Make me new ones." And the new ones work out splendidly. >> Oh my god. >> They fit like puzzle blocks. >> Oh my god. Like that like single singular subtle insight. >> That subtle insight from his lab mate Jerry Donahghue to to turn from keto. >> Um they exist in keto and amino forms and not in the enol form. Meaning that the hydrogen was in the wrong place. But now when the hydrogen is in the right place, the hydrogen of one is going to hydrogen bond with the nitrogen of the other or the oxygen of the other. And they're going to create these weak bonds

1:07:21in the middle. The other thing that was crazy was that when they had the A and the T >> Mhm. >> and the G and the C >> Mhm. There was structural consistency because the A and the T is pairing two carbon rings with one carbon ring and two carbon rings with one carbon ring. Meaning the distance between the backbones was going to be the same, right? And we and there's a you see you've got >> you've got the the C and the G. >> Yes. >> Those have three hydrogen bonds between them. >> The A and the T have two. In that case, that's a U, but same thing, right?

1:08:02>> Yeah. Yeah. >> But notice that the distance between the phosphate backbone on the top and the bottom are the same. >> So, so we're looking at an image where in the middle we have on the left the G and the C with three hydrogen bonds in the middle and on the right the the A and the I guess it's supposed to be a T. >> Yeah, that's a U for the RNA, but it's it's the same structure. >> Sorry, T with two hydrogen bonds. And the point is when you look at it at like top to bottom even though there's a difference in pair number >> the the the distance is is identical. >> Yes. >> Which means it can be a a structure. >> Which means it can be a structure. It can be a Lego block where I can swap out A's and T's and A's and T's. But the

1:08:44overall structure remains the same. >> Yes. >> So I've just created a code. >> Yes. >> Where? >> Yes. >> The the the the Lego blocks themselves are different. But when you extrapolate to the larger molecule, >> it fits. >> It fits. And they're all the same. Which means that whatever physics is happening here in this location, let's say there's more A's and less T's. In that location, there's the other way around. The physics is going to be the same. The rope is going to look the same. >> Same. Yes. >> Right. >> Yes. No. This that >> the rope might be colored differently. >> Right. Right. Right. Right. Right. >> But the physics of the rope is going to be the same. It's the a periodic crystal that Schroinger was talking about has fin

1:09:25they finally now found the missing piece for what is required to actually create the physical structure of this a periodic crystal which initially there was like oh it's a triple helix cuz again we [clears throat] have to remember there's no conception there's no concept of what the structure they're just trying to figure out what what what is going on they know that these are the building blocks but they're like does it go this way does it this way. >> Are there three? Are there five? >> God. And and that one flip of the the the the not enal form but the keto and amino form that of the hydrogen which