Stefan Dr. Marcinowski

Crystallization of human tumour necrosis factor

Abstract Crystals of recombinant human tumour necrosis factor, an 157 amino acid protein expressed in Escherichia coli , have been obtained that are suitable for a full structure determination. A dramatic increase in crystal size was obtained with the addition of the non-ionic detergent β -octyl glucoside. The crystals belong to the trigonal space group P3 1 21 with unit cell dimensions a = b =166.0 a and c =93.0 a, and diffract to 2.9 a. Crystal density measurements indicated a solvent content of close to 65%. Since TNF has been proposed to exist at the trimer in solution, this is consistent with an arrangement of two independent trimers, i.e. six molecules, in the asymmetric unit.