Comment by flobosg

2 years ago

> AlphaFold is amazing homology modeling

If it is homology modelling, then how can it work without input template structures?

It has template structures. AlphaFold uses the following databases:

    BFD,
    MGnify,
    PDB70,
    PDB (structures in the mmCIF format),
    PDB seqres – only for AlphaFold-Multimer,
    Uniclust30,
    UniProt – only for AlphaFold-Multimer,
    UniRef90.

  • Those databases are used to derive the evolutionary couplings and distance matrices used by the algorithm. Several of those databases aren’t even structural ones. Furthermore, AlphaFold can function with only a MSA as an input, without retrieving a single PDB coordinate.

    • It's all about boosting signal by finding other proteins that are similar, until you get to the point that you can identify a fold to assign to a region of the protein. That's why some are structural, and some are not.

      >Furthermore, AlphaFold can function with only a MSA as an input, without retrieving a single PDB coordinate.

      Yes, it has a very nice model of what sequences should look like in 3D. That model is derived from experimental data. So if I give AlphaFold an MSA of a new, unknown protein fold (substantively away from any known fold), it cannot predict it.

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