The @DeepMind protein folding result is really incredible, and incredibly important. But I know it’s pretty tricky to understand, so here’s a megathread, with a bit of Biology 101, for @holland_tom@thehistoryguy
et al.
@DeepMind@holland_tom@thehistoryguy But in the body, proteins only work as three-dimensional clumps, precisely folded. The way the protein folds up is determines by its amino acid sequence. And this is the bit we struggle with.
(that is a wretched viral protein btw)
Until now, it has been nigh on impossible to work out the 3D structure of a protein based on its amino acid sequence. It’s like knowing all the words, but them only being useful in a sentence.
So when we look at some DNA, we can translate it into an amino acid string, but not into a 3D – that is, functional - protein.
Bear in mind that *ALL* life is either made of, or by proteins. So understanding the process from the gene sequence to the working protein is fundamental to biology.
But it’s also very important for studying diseases. A genetic disease which is caused by a mutation in a DNA sequence can alter the amino acid sequence, and therefore the 3D structure.
A single letter change in the DNA of the globin gene will result in a single amino acid change, and a mis-shaped globin protein, and the result is Sickle Cell anaemia.
We have been working out how proteins are shaped in 3 dimensions using techniques such as X-Ray crystallography. But we can't predict its shape from the original DNA or amino acid sequence.
What DeepMind has done is use AI to make that prediction - an extraordinarily complex process of calculation, trial and error and guess work under very specific biological rules - and go from DNA to 3D protein.
It's radical cos it means we can predict now how mutations in DNA will change the function of a protein.
That will be incredibly important for fundamental biology, for studying diseases, and for designing drugs that treat diseases that are fundamentally born of misfolded proteins.
As @matthewcobb mentions, we still don't know how the process works, cos <black box AI mystery theatre 3000> but the prediction machine works.
Earlier attempts included gamifying the process, which let's face it, is really cool. FOLDIT was a way to make 3D structure competitive, and worked much better than any other technique then available.
I made a short film about this a few years ago bit.ly/2Jun4HL
This is all going to be on #BBCInsideScience on Thursday btw, presented by the awesome @thermoflynamics, who knows A LOT about proteins.
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I'm seeing a lot of chat about PCR and COVID, some of it quite bonkers. So here’s a PCR 101.
DNA is very small and therefore not easy to detect. PCR is a tool for multiplying specific bits of DNA from a few to billions, thus making it easy to detect. 1/n
PCR is a standard tool in molecular biology, and has been for decades. It was, by the way, invented by Kary Mullis, who claims to have come up with the idea whilst tripping balls on LSD. Mullis was a bit of a jerk btw, an AIDS and Climate Change denialist. 2/n
Right, so DNA is a DOUBLE helix, meaning it has two strands made up of chains of just 4 ‘letters’ that pair up in a specific way (that is, ‘complementary’): A pairs with T, C pairs with G. a bit like this.
My quick James Randi story. I only met him once, and he told me this tale, which you could stop at almost any point and it would still be an amazing story. He said… 1/n
‘When I was on Happy Days, the Fonz and I were going to have lunch with Richie Cunningham…’
I mean, it’s a good opener.
We went to a Mexican restaurant, that was set back from the street by a long dark corridor, the only light for which came from the street door. As we were in this tunnel, suddenly, the light is blocked and we are in pitch black. 3/n
In fact, I think the Government should take a stand on all manner of academic disputes and topics. Group selection? WHO IS THE MINISTER FOR ANTS.
Abiogenesis: WILL THE RIGHT HONOURABLE MEMBER CLARIFY IF SHE SUPPORTS THE RNA WORLD HYPOTHESIS DESPITE THE FACT THAT THERMODYNAMIC EQUILIBRIUM VIA PROTON GRADIENTS IS A BETTER EXPLANATION FOR THE TRANSITION FROM GEOCHEMISTRY TO BIOCHEMISTRY IN THE HADEAN?
Ok, a quick thread on white supremacy symbols - I spend a lot of time on white supremacy forums online, and they have dozens of really idiotic numerical codes, most of which are substitution ciphers that a 7 year old would come up with.
Darren appears to have these two on his face
88 = HH = Heil Hitler
23/16 = WP = White Supremacy
There's also:
18 = AH = Adolf Hitler
1488: a reference to the so-called 14 words, coined by white supremacist terrorist David Lane
There's also:
1/11 = AK = Aryan Knights
3/11 = 3 K = KKK
109 = the claim that Jews have been expelled from 109 nations throughout history, sometimes coupled with
110 = in the hope that the US will be the next one
#LongCovid: a thread. Back in March, I was on @BBCr4today talking to @Marthakearney about getting Covid19. I was pretty upbeat, and predicted I would be better in a few days. This alas is not what happened. I wasn’t hospitalised but, like 100s of 1000s, was seriously ill 1/n
@BBCr4today@Marthakearney Six months on, #LongCovid is beginning to be recognised. I have very mild but not inconsequential symptoms: the most common being shortness of breath and fatigue 2/n
But many others have much more serious after-effects of the initial infection. Fatigue isn’t just tiredness, but includes anxiety, PTSD and depression. We made a programme about this, on @BBCRadio4 at 11am today. bbc.in/2S5Tdq7
They were of course able to *drink* milk, just unable to digest milk in adulthood before the evolution of lactase persistence. Before that, they were eating soft cheeses and yoghurts, in which the sugar lactose is already broken down.
The mutation itself is not in the gene LCT itself, but around 13,000 base pairs upstream in a control region; this C>T change accounts for the majority of lactase persistence.