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 190C. 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).
        
Representative scheme of Haloalkane_dehalogenase-HLD2 structure and an image from PDBsum server
Databases
PDB-Sum
4F5Z Previously Class, Architecture, Topology and Homologous superfamily - PDB-Sum server
FSSP
4F5ZFold classification based on Structure-Structure alignment of Proteins - FSSP server