Revisiting Eck and Dayhoff's Building Block Model of Ferredoxin Evolution on Dayhoff's 100th Birthday.

ABSTRACT: Nearly 60 years ago, Eck and Dayhoff (Science 152:363-366, 1966) aligned amino acids from first and second halves of a ferredoxin sequence, revealing a symmetric CX₂CX₂CX₃CX₁₈CX₂C₂C₃C spacing signature in which X_n denoted intervening residues. This symmetry, along with other cyclic patterns, suggested that a tandem duplication shaped ferredoxin evolution and that the ancestral sequence may have drawn from a reduced amino acid repertoire. Here, I revisit the duplication model using the deep learning-based AlphaFold2 ab initio pipeline, benchmarked against the I-TASSER threading tool. Predicted ancestral structures were obtained with high confidence, with some aligning to the two halves of a reference fer

SUBMITTER: Caetano-Anolles G 

PROVIDER: S-EPMC12920312 | biostudies-literature | 2026 Feb

REPOSITORIES: biostudies-literature