Watson’s failed triple-helix model

49:38>> Yes. Yes. And they're trying to find it, right? >> Franklin and Gosling. Now we're back in King's College, London. What they figure out is there's actually two different types of DNA in the sample that they got. Okay. Okay. There's A DNA and BD DNA. And it has to do with two different types of humidity. Okay. Something that has something that's super dehydrated is called ADNA. And that's what Rosalyn Franklin was really after. And then there's something that has a bunch of humidity, a bunch of water molecules there, and that's the BDNA. The way they're doing this is actually incredible. They take single bits of DNA like strings, okay? And they they they

50:21pull these wires like spiderw webs and they put it in front of their X-ray machine and they take photographs with the X-ray machine and the exposures are something like 60 hours. >> They're exposing this thing because it's a tiny little thing, right? So, you need a really long time exposure to capture all of that information. >> That makes sense, >> right? So there's two different types of DNA that they're looking at. Franklin is looking at both. She gives an internal talk at Kings, okay? Explaining that there's these two different types. Um the phosphates, the phosphate groups that I was talking about in those building blocks, those phosphates lie on the outside. >> Um and there's some kind of helical

51:02structure that they've already found because >> they see these X's, right? The the stuff that Francis Crick was talking about. They've already seen these X's. So They're seeing a helical form. >> Okay. >> Um Rosalyn Franklin gives a seminar. >> Okay. >> In King's College. >> Yes. >> Where she's talking about her work. >> Yes. >> James Watson is in attendance. >> Okay. >> In that seminar. >> Okay. So the op So the point is we have we have we have someone from this block and someone from that block. They're both trying to be the best. >> Yeah. >> And then so Franklin on her block is like I'm gonna preach the gospel. >> Yeah. I'm I'm gonna do the actual experimental work. And then and then Watson rolls up. >> Watson rolls up. He he's in the back of

51:44the seminar. >> He's kind of peeping game. He's like like what's going on over here? >> Yeah. [laughter] And and he's and he and he goes to the seminar. Okay. >> He's extremely excited. He comes back to to Cavendish. He goes to Crick >> and he's like this is this is all the stuff that they were talking about in the seminar. He misreme >> what happened in the seminar. >> He didn't have a voice memo. >> No, he and he didn't have the chemistry background really to really understand what was going on. and internalize. So he tells Francis Crick about all these things. They get to working. >> Yeah. >> They create a model and at that time um Watson and Crick were really >> into making Lego models. These are like

52:24little stick figurine models of the they're like okay this is what the purine looks like. It's a hexagon with these little sticks and the and the stick represents a hydrogen and the the hexagon represents carbon ring and so on and so forth. So they start creating this model and they think they have a model. Okay, it's it's a triple helix. There's three strands that are going out. >> The phosphates are on the inside >> because he misreme but he's like really excited. [laughter] >> He's like, "Oh, this might work." >> Um, >> so the Cavendish group called the Kings London, the Kings College group to to come on down, get your car, come on down, check it out. >> So Rosen Franklin rolls up, >> okay? demolishes them.

53:07Okay. In the presence of Lawrence Bragg, who's the director of Caendish, she's like, "This is wrong. This is wrong. This is wrong. This is just stupid." [laughter] Right? [snorts] And um in in Watson's garbled account, they've they've built this three-stranded helix and the the data contradicts what the model they've built. Cavendish is embarrassed. >> Embarrassed. >> Embarrassed. Okay. Lawrence Bragg is like, "You need to stop. [laughter] >> This is in 1951. >> You're making us look bad." >> Yeah. Yeah. >> Stop it. >> Stop it. So Lawrence Bragg is like, "This this is no. This is not what we do

53:49in Cavendish, >> right? The most one of the most like again one of the most legendary." >> Yeah. This he this guy's a legend. He won the Nobel Prize at 25. He's telling you to stop. He's in charge. Stop. >> They stop. Okay. They stop. In 1951, they stopped. >> This is incredible. >> It's it's it's it's actually incredible. Then, >> okay, >> um the King's College group still keeps going on. They still keep collecting data. In 1953, early 1953, they get wind of a guy named Lionus Powing. >> When you say they, who? >> This is both King's College >> and Caendish. >> And Cavendish. The Brits. >> Okay. The Brits. The Brits get wind of

54:30the Americans. >> The Americans. >> Okay. [laughter] Because Lionus Powing at Caltech, >> yeah, >> has just discovered the structure of the alpha helix. The alpha helix is a fundamental building block of proteins. Okay. there's a helical structure that um almost a lot of proteins have this helical structure that is sort of it's called a secondary structure that is used to build the tertiary big 3D structure. Okay. You build a bunch of these alpha helixes together and you make like whatever protein you want. But this is a >> it's a single Lego block that makes the thingy you want to make of your

55:11>> Lego. Exactly. Exactly. Right. and and Lionus Powing comes out with this manuscript of the alpha helix. He's incredibly good at chemistry, trained under Neil's Boore. >> Yeah. Dangerous. >> Dangerous. [laughter] Okay. >> Everyone's sweating over it. >> And and and and he's he comes out with this. The Caendish guys are like, "Wow, he just scooped us because they were working on the same thing." >> Okay. >> Okay. >> Okay. And at the same time in 1953, Lionus Powing comes out with his version of the DNA helix. >> Okay. >> It is the same triple helix. Very similar this three stranded helical

55:52structure that Watson and Cric had done that was wrong. >> Correct. >> Right. Because he has limited data. He doesn't actually know the data >> cuz cuz he doesn't have the source. >> Yeah. He's he hasn't been to King's College. If he was at that seminar, he's a chemist. Yeah, he would have figured it out. >> So the point is that that at Kings they were getting source data because of their expertise in being able to do the X-ray crystalallography. >> Exactly. >> And so they like had basically the best map >> for where the treasure is. >> Yes. >> And and the uh Watson and Craig only got were able to get to it cuz they were local. >> They were local down the road whatever and we're able to see it. Now at Caltech, Powelling, he he is intuiting

56:33this without having a really good map.