1. Data set
A single asymmetric chain structure was adopted in the PDB archive on the condition that the length of the chain was 8, the sequence identity was 90% or less, and that there were no heteroatoms. Structures which only contains protein without nucleic acids of DNA, RNA, or DNA-RNA hybrid was selected. Two structures of 1n9v and 1oeh was set. And 1oeh was abandoned because it was fragmented. Finally, 1n9v which is the angiotensin peptide was used in this work. ‘DRVYIHPF’ is the amino acid sequence of 1n9v.