CheShift-2 (pronounced /tʃeʃɪft/) is an application created to compute 13Cα and 13Cβ protein chemical shifts and to validate protein structures. It is based on quantum mechanics computations of 13Cα and 13Cβchemical shift as a function of the torsional angles (φ, ψ, ω and χ1, χ2) of the 20 amino acids.CheShift-2 can return a list of theoretical chemical shift values from a PDB file. It also can display a 3D protein model based on an uploaded PDB file and chemical shift values.