ENGINEERING SURFACE LOOPS OF PROTEINS - A PREFERRED STRATEGY FOR OBTAINING NEW ENZYME FUNCTION

A prerequisite for the rational redesign of enzymes is that altering a mino acids in an attempt to obtain new biological function does not un expectedly alter the globular, natural framework of the native protein on which the design is being executed. The results of combinatorial-m utagenesis strategies suggest that random variation of amino acid sequ ence is most easily tolerated at the solvent-exposed surfaces of a pro tein. This review analyses effective redesigns of Bacillus stearotherm ophilus lactate dehydrogenase (bsLDH), in which all residue variations are at solvent-exposed surfaces. The majority of these variations wer e located within surface loops, which interconnect stable secondary st ructures traversing the globular core of the protein.