CHARACTERIZATION OF NONPOROUS MAGNETIC CHELATOR SUPPORTS AND THEIR USE TO RECOVER POLYHISTIDINE-TAILED T4 LYSOZYME FROM A CRUDE ESCHERICHIA-COLI EXTRACT

The use of high capacity micron-sized non-porous magnetic metal chelat or adsorbents for the direct recovery of a recombinant metal-binding p rotein from crude liquors is described. Selectivity and interaction st rength of magnetic chelator particles were assessed using a set of nat ive proteins with known behaviour towards commercially available immob ilised metal chelate adsorbents. Particles charged with Cu2+ were high ly effective in recovering a recombinant histidine-tailed T4 lysozyme fusion protein directly from crude E. coil extracts in a single step. Levels of recovery and purity were high and compared favourably with t hose achieved by chromatography of pre-clarified extracts on Cu2+-IDA Sepharose. The magnetic approach offers advantages such as the avoidan ce of clarification to prevent fouling of chromatography columns, step s that become especially significant at large scale. By detailed chara cterisation of the magnetic chelators the practical use of tailed T4 l ysozyme for repeated production of periplasmic products is a realistic prospect. (C) 1997 Elsevier Science B.V.