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AlphaFold: a solution to a 50-year-old grand challenge in biology

deepmind.com

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Re: AlphaFold: a solution to a 50-year-old grand challenge in biology

#91

Title as submitted is hyperbole, please fix?

I agree. "AlphaFold achieves a median score of 87.0 GDT". While this is a major advance, to me 100 GDT would be 'solved', not 87.

> To me

Are you a domain expert? Because:

> According to Professor Moult, a score of around 90 GDT is informally considered to be competitive with results obtained from experimental methods.

Re: AlphaFold: a solution to a 50-year-old grand challenge in biology

#92
post #36

This is a big step forward, but the outstanding question as far as to whether or not this is useful for evaluating novel proteins, is going to be how good is the confidence metric at telling the user to trust or not trust the results. You can see from their examples, that AlphaFold is very good but not perfect. I imagine for some proteins it will still give misleading or erroneous results and if you can’t tell when t…

Every simulator is going to have error. In this case this biennial challenge represents the computational state of the art with scores of 30-40 over the last decade. The AlphaFold2 model sends that score up to 87 with errors about than the width of the atom. You can actually see the difference between their prediction and the actual result and it’s stunning. This is all on the blog site so I recommend reading before throwing shade.

Re: AlphaFold: a solution to a 50-year-old grand challenge in biology

#93
post #37

Earlier quoted context omitted.

We can already determine how a few proteins (170k — which sounds like a lot, but which is only 0.09% of all currently-catalogued protein sequences) fold by experimental work. What an accurate model of protein folding allows us to do, is to take our big database of DNA, predict protein foldings for all of it, and then stand up a search index for this database, keying each amino-acid "row" by the "words" of its predict…

Considering that this system "uses approximately 128 TPUv3 cores (roughly equivalent to ~100-200 GPUs) run over a few weeks" to determine a single protein structure, making predictions for all proteins encoded in a human genome seems impractical at this stage. With luck, this advance will help lead to discovery and definition of new folding rules and optimizations that will make protein folding predictions for the wh…

[deleted]

Re: AlphaFold: a solution to a 50-year-old grand challenge in biology

#94
post #78

Earlier quoted context omitted.

Art's a smart guy and I have a lot of respect for his biological intuition, but his understanding of computational biology is very limited.

I would imagine that he is not assessing this advancement merely using his own personal expertise, but rather the combined expertise of the resources he represents. CEOs don't just look at problems and potential solutions. They have people who look at those things, and then tell them their opinion. In any case, you've picked a nit with one of the three people quoted. Any objections to the other two?

My main objection to Vivek (the Nobel Prize winner) is the prize in that case should have gone to my advisor, Harry Noller. John Moult... he's a nice guy but I think he's being a bit breathless here.

Re: AlphaFold: a solution to a 50-year-old grand challenge in biology

#95
post #20

This sounds wonderful and frightening. On the one hand, now we can engineer drugs at light speed. But wasn't protein folding supposed to be NP-hard? Can deep learning find the cracks in P vs NP? Perhaps making clever guesses at prime factors because it learned some weird structural fact that has eluded mathematicians. If we break crypto, there goes the modern world. Banks, bitcoin, privacy, Internet, the whole sheban…

NP-hard doesn’t say how hard it is to solve finite problems. Even for n = 1,000,000, O(e^n) isn’t necessarily problematic, if the constant is small enough, or if you throw enough hardware at it.

This “uses approximately 128 TPUv3 cores (roughly equivalent to ~100-200 GPUs) run over a few weeks”. That is a moderate amount of hardware for this kind of work, so it seems they have a more efficient algorithm.

Also, this algorithm doesn’t solve protein folding in the mathematical sense; it ‘just’ produces good approximations.

Re: AlphaFold: a solution to a 50-year-old grand challenge in biology

#96
post #53

Pretty interesting that they only used about $15k worth of resources (retail price) to achieve this. It's not a technique that would have been out of reach for other organizations based only on not being able to afford the compute.

Based on the going rate of a 32-core TPUv3 slice ($32/hr USD) running "for a few weeks", isn't this closer to $65k USD?

Re: AlphaFold: a solution to a 50-year-old grand challenge in biology

#97
post #36

This is a big step forward, but the outstanding question as far as to whether or not this is useful for evaluating novel proteins, is going to be how good is the confidence metric at telling the user to trust or not trust the results. You can see from their examples, that AlphaFold is very good but not perfect. I imagine for some proteins it will still give misleading or erroneous results and if you can’t tell when t…

> the outstanding question as far as to whether or not this is useful for evaluating novel proteins That is not an outstanding question. The test on which DeepMind scored high marks is a test of how well the algorithm folds novel proteins -- proteins whose ground-truth structure has not yet been published.

We’d have to see the distribution of GDT scores evaluated on unknown proteins to say anything about how confident we can be. If the distribution is tightly distributed around the median then great, this works really well. If the variance is large though then you’re going to have a hard time using this for meaningful predictions.

Re: AlphaFold: a solution to a 50-year-old grand challenge in biology

#98
post #37

Earlier quoted context omitted.

We can already determine how a few proteins (170k — which sounds like a lot, but which is only 0.09% of all currently-catalogued protein sequences) fold by experimental work. What an accurate model of protein folding allows us to do, is to take our big database of DNA, predict protein foldings for all of it, and then stand up a search index for this database, keying each amino-acid "row" by the "words" of its predict…

Considering that this system "uses approximately 128 TPUv3 cores (roughly equivalent to ~100-200 GPUs) run over a few weeks" to determine a single protein structure, making predictions for all proteins encoded in a human genome seems impractical at this stage. With luck, this advance will help lead to discovery and definition of new folding rules and optimizations that will make protein folding predictions for the wh…

My reading based on context was that this was time to train, not time to predict.

Re: AlphaFold: a solution to a 50-year-old grand challenge in biology

#99
post #20

This sounds wonderful and frightening. On the one hand, now we can engineer drugs at light speed. But wasn't protein folding supposed to be NP-hard? Can deep learning find the cracks in P vs NP? Perhaps making clever guesses at prime factors because it learned some weird structural fact that has eluded mathematicians. If we break crypto, there goes the modern world. Banks, bitcoin, privacy, Internet, the whole sheban…

Far from an expert on complexity theory, but NP-hard problems can be approximated in polynomial time. With Deep Learning you are doing approximation. So this is nothing ground breaking in that respect.

That actually isn't totally true. Approximate methods, in the formal sense, require a guarantee that they perform within X of the optimal solution. Not all NP-hard problems have polynomial approximations and the methods shown here are likely not approximations because they very likely provide no guarantees on performance. They provide zero guarantees.

Re: AlphaFold: a solution to a 50-year-old grand challenge in biology

#100
post #33

Now onto the much harder problem of doing the reverse: taking an arbitrary structure and determining an amino-acid sequence that will fold into it.

I assume if the forward direction is fast enough, the reverse could be done by evolutionary methods.
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