Compositions and methods are provided that are useful for predicting and controlling the stability of expressed polypeptides. The compositions and methods may be used to predict and as desired, increase or decrease the stability of proteins recombinantly expressed in mycobacteria, for example DesA3 expressed in Mycobacterium smegmatis. At the C terminus and the penultimate position, substitution to residues with charged side chains, large non-polar side chains, or no side chains can be used to reduce or inhibit the protein degradation. At the antepenultimate position from the C terminus, residues with no side chain or acidic side chains can increase the stability, i.e. reduce or inhibit the protein degradation. The combinational substitution of only the last three residues of polypeptides can make the polypeptides more stable during heterologous expression in mycobacterial hosts.