Expression of bovine pancreatic ribonuclease A in Escherichia coli

Abstract

A synthetic gene for bovine pancreatic ribonuclease A (RNase A) has been expressed in Escherichia coli as a fusion protein with β‐galactosidase linked by the tetrapeptide Ile‐Glu‐Gly‐Arg. RNase A was cleaved from the fusion using factor Xa, and the resulting product prufied and reconstituted. The isolated RNase A was chromatographically, catalytically, and immunologically indentical with authentic RNase A. This work argues that the method suggested by Nagai and Thogersen [Nagai, K. & Thogersen, H. C. (1984) Nature (Lond.) 309, 810–812] for releasing fusion proteins is quite general, even when applied to a particularly complicated expression problem. The procedure here makes RNase A available for the first time as a model for studying structure‐function relationships in proteins using site‐directed mutagenesis. Copyright © 1987, Wiley Blackwell. All rights reserved