sentences:  The position of this pseudo-Cβ atom (pCβ) is derived from the positions of preceding
  Cα−1 and the following Cα+1.The Cα-pCβ vector is calculated by adding the
  Cα−1-Cα0 and Cα+1-Cα0 vectors.HSE is used in predicting discontinuous B-cell epitopes.