Coronaviruses M proteins are well-represented in the major protein component of the viral envelope . During the viral assembly, they play an important role by association with all other viral structural proteins . Despite their crucial functions, very little information regarding the structures and functions of M proteins is available . Here we utilize bioinformatic tools from available sequences and 3D structures of SARS-CoV, SARS-CoV2, and MERS-CoV M proteins in order to predict potential B-cell epitopes and assessing antibody binding affinity . Such study aims to aid finding more effective vaccines and recognize neutralizing antibodies . we found some rather exciting differences between SARS-COV-2, SARS-Cov and MERS-CoV M proteins . Two SARS-CoV-2 peptides with significant antigen presentation scores for human cell surface proteins have been identified . The results reveal that N-terminal domains of M proteins of SARS-CoV and SARS-CoV2 are translocated (outside) whereas it is inside (cytoplasmic side) in MERS-CoV.