Amphipathic alpha-helices and putative cholesterol binding domains of the influenza virus matrix M1 protein are crucial for virion structure organisation

•Functionnally relevant and highly conservative α-helices and cholesterol binding (CRAC) motifs on 6 of the α-helices of the M1 protein were predicted by in vitro modelling.•CRAC motifs on α-helices 3 and 6 are predicted to interact with the viral membrane.•Mutational analysis of CRAC motifs confirms the significance of α-helices 2, 3, 6 and 8 in M1 in virion morphology.