biostudies-literatureUnknown9Blaber Mβ-trefoil proteins exhibit an approximate C₃ rotational symmetry. An analysis of the secondary structure for members of this diverse superfamily of proteins indicates that it is comprised of remarkably conserved β-strands and highly-divergent turn regions. A fundamental "minimal" architecture can be identified that is devoid of heterogenous and extended turn regions, and is conserved among all family members. Conversely, the different functional families of β-trefoils can potentially be identified by their unique turn patterns (or turn "signature"). Such analyses provide clues as to the evolution of the β-trefoil family, suggesting a folding/stability role for the β-strands and a functional role for turn regions. This viewpoint can also guide <i>de novo</i> protein design of β-tFrontiers in molecular biosciences889943https://www.ebi.ac.uk/biostudies/studies/S-EPMC9062101biostudies-literatureVariable and Conserved Regions of Secondary Structure in the β-Trefoil Fold: Structure Versus Function.PMC9062101Blaber MfalseVariable and Conserved Regions of Secondary Structure in the β-Trefoil Fold: Structure Versus Function.β-trefoil proteins exhibit an approximate C₃ rotational symmetry. An analysis of the secondary structure for members of this diverse superfamily of proteins indicates that it is comprised of remarkably conserved β-strands and highly-divergent turn regions. A fundamental "minimal" architecture can be identified that is devoid of heterogenous and extended turn regions, and is conserved among all family members. Conversely, the different functional families of β-trefoils can potentially be identified by their unique turn patterns (or turn "signature"). Such analyses provide clues as to the evolution of the β-trefoil family, suggesting a folding/stability role for the β-strands and a functional role for turn regions. This viewpoint can also guide <i>de novo</i> protein design of β-t2022-01-01T00:00:00Z20222025-05-18T12:05:30.361Z2025-04-05T20:39:28.538ZS-EPMC90621013551785810.3389/fmolb.2022.889943