Engineering Enzyme Stability and Resistance to an Organic Cosolvent by Modification of Residues in the Access Tunnel

Mutations targeting as few as four residues lining the access tunnel extended the half-life of an enzyme in 40 % dimethyl sulfoxide from minutes to weeks and increased its melting temperature by 19 °C. Protein crystallography and molecular dynamics revealed that the tunnel residue packing is a key determinant of protein stability and the active-site accessibility for cosolvent molecules (red dots).