CLONING AND CONTROLLED OVEREXPRESSION OF THE GENE ENCODING THE 35 KDASOLUBLE LYTIC TRANSGLYCOSYLASE FROM ESCHERICHIA-COLI

The lytic transglycosylases of Escherichia coli are involved in peptid oglycan metabolism and resemble the lysozymes not only in activity, bu t in the case of the 70 kDa soluble lytic transglycosylase (Slt70), al so structurally. Here we report the cloning of the gene that encodes t he 35 kDa soluble lytic transglycosylase (Slt35) of E. coli. Based on the sequence of the full-length gene, Slt35 is very likely to be a pro teolytically truncated form of a slightly larger protein. The homology between Slt35 and Slt70, albeit poor, indicates that the active site architecture of both proteins may be alike. Using the T-7 promoter sys tem, Slt35 was overproduced in large quantities and purified to homoge neity for crystallographic purposes.