The Transforming growth factor beta receptor 2 ectodomain is a compact fold consisting of nine beta-strands and a single helix stabilised by a network of six intra strand disulphide bonds. The folding topology includes a central five-stranded antiparallel beta-sheet, eight-residues long at its centre, covered by a second layer consisting of two segments of two-stranded antiparallel beta-sheets (beta1-beta4, beta3-beta9) [1].

1: Crystal structure of the human TbetaR2 ectodomain--TGF-beta3 complex. Hart PJ, Deep S, Taylor AB, Shu Z, Hinck CS, Hinck AP; Nat Struct Biol. 2002;9:203-208. PMID:11850637