15N, 13C and 1H resonance assignments and secondary structure determination of a variable heavy domain of a heavy chain antibody

Heavy chain antibodies differ in structure to conventional antibodies lacking both the light chain and the first heavy chain constant domain (CH1). Characteristics of the antigen-binding variable heavy domain of the heavy chain antibody (VHH) including the smaller size, high solubility and stability make them an attractive alternative to more traditional antibody fragments for detailed NMR-based structural analysis. Here we report essentially complete backbone and side chain 15N, 13C and 1H assignments for a free VHH. Analysis of the backbone chemical shift data obtained indicates that the VHH is comprised predominantly of β-sheets corresponding to nearly 60 % of the protein backbone.