English: Architectural details of AlphaFold 2. a, Evoformer block. Arrows show the information flow. The shape of the arrays is shown in parentheses. b, The pair representation interpreted as directed edges in a graph. c, Triangle multiplicative update and triangle self-attention. The circles represent residues. Entries in the pair representation are illustrated as directed edges and in each diagram, the edge being updated is ij. d, Structure module including Invariant point attention (IPA) module. The single representation is a copy of the first row of the MSA representation. e, Residue gas: a representation of each residue as one free-floating rigid body for the backbone (blue triangles) and χ angles for the side chains (green circles). The corresponding atomic structure is shown below. f, Frame aligned point error (FAPE). Green, predicted structure; grey, true structure; (Rk, tk), frames; xi, atom positions.