Extracellular domain of type I receptor for transforming growth factor-beta: molecular modelling using protectin (CD59) as a template

We have observed that the extracellular domain of TβRI and protectin (CD59), an inhibitor of the membrane attack complex of complement, share structural features, a distinct spacing of ten cysteines and a C‐terminal ‘Cys‐box’. Based on these common features and the recently determined NMR‐structure of protectin, a three‐dimensional model for the extracellular domain of TβRI was constructed. After energy minimization and molecular dynamics simulation, a structure with four extending fingers (pes quattvordigitorum) and two clusters of charged residues was obtained. This model provides a view to the understanding of interactions between TβRI, TβRII and TGFβ during ligand recognition and signal transduction.