(A) H bonds between RBD of nCOV-2019 and SARS-COV. (B) Mapping contribution of interface residues to structure in the RBD of nCOV-2019. The RBD is purple and the ACE2 is yellow. The RBD in contact with AC2 is rendered in a surface format with more red being a favorable contribution to binding (more negative) and blue unfavorable contribution (positive).