POLY(ETHYLENE) GLYCOL MONOMETHYL ETHERS - AN ALTERNATIVE TO POLY(ETHYLENE) GLYCOLS IN PROTEIN CRYSTALLIZATION

Poly(ethylene) glycol monomethyl ethers (Peg-mmes) are a series of met hyl substituted poly(ethylene) glycols that have been used with some s uccess in the crystallization of a number of hydrophobic proteins. Cry stallization of a lipase from Humicola lanuginosa complexed with the C 12 substrate analogue from Peg-mme 5000, an endoglucanase 1 and a 59 k Da fragment of human topoisomerase Ila crystallized from Peg-mme are d escribed. The use of Peg-mme for improving the quality of crystals pre viously grown from normal poly(ethylene) glycol 8000 is also described . We suggest that these modified Peg-mmes should be regularly used in screening for crystallization.