I have used Swissmodel, MODELLER, Phyre, Robetta and I-TASSER for modelling my protein, but in the modelled structure, amino acid is not observed at a specific position to which I want to induce a mutation. That amino acid is present in sequence, but absent in modelled structure of all these mentioned tools. Is there any other way of modelling a structure that covers maximum sequence coverage so that I find that residue at its intended position in modelled structure?