C-terminal β-strand swapping in a consensus-derived fibronectin Type III scaffold

• Published in: Proteins, structure, function, and bioinformatics structure, function, and bioinformatics, 2014-07, Vol.82 (7), p.1359-1369
• Main Authors: Teplyakov, Alexey, Obmolova, Galina, Malia, Thomas J., Luo, Jinquan, Jacobs, Steven A., Chan, Winnie, Domingo, Derrick, Baker, Audrey, O'Neil, Karyn T., Gilliland, Gary L.
• Format: Article
• Language: English
• Subjects: 3D domain swapping; alternative scaffold; Amino Acid Sequence; Crystallography, X-Ray; fibronectin Type III domain; Fibronectins - chemistry; Fibronectins - metabolism; Models, Molecular; Molecular Sequence Data; Protein Structure, Tertiary; Protein Subunits - chemistry; Protein Subunits - metabolism; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - metabolism; Sequence Alignment; tencon; X-ray structure; β-strand swapping
• ISSN: 0887-3585; 1097-0134
• DOI: 10.1002/prot.24502

ABSTRACT The crystal structures of six different fibronectin Type III consensus‐derived Tencon domains, whose solution properties exhibit no, to various degrees of, aggregation according to SEC, have been determined. The structures of the five variants showing aggregation reveal 3D domain swapped dimers. In all five cases, the swapping involves the C‐terminal β‐strand resulting in the formation of Tencon dimers in which the target‐binding surface is blocked. All of the variants differ in sequence in the FG loop, which is the hinge loop in the β‐strand‐swapped dimers. The six tencon variants have between 0 and 5 residues inserted between positions 77 and 78 in the FG loop. Analysis of the structures suggests that a non‐glycine residue at position 77 and insertions of