A molecular model of mature dengue virus envelope building block consisting of two E and two M protein subunits is constructed. Monte Carlo optimisation is performed for the model in the implicit membrane system. Interactions between the ectodomains and membrane parts of E and M proteins are studied, and possible role of conserved residues is suggested. The opening of E protein detergent binding site and its fixation in the open state by the M non-structured loop is observed. (c) 2012 Elsevier Inc. All rights reserved.