High-level Secretion of Human Cardiodilatin by Escherichia coli

Abstract

A gene encoding human cardiodilatin (hCDD; a vasodilating polypeptide located on the N-terminal portion of γ human atrial natriuretic polypeptide) was fused to the secretion signal coding sequence of the Escherichia coli outer membrane protein F (OmpF). This hybrid gene was preceded by a chemically synthesized consensus ribosome binding sequence and was expressed in E. coli under the transcriptional control of the tac (trp:lac fusion) promoter. On the addition of isopropy-β-D-thiogalactopyranoside (IPTG), cells secreted about 17-30mg of hCDD per liter broth. On induction at OD₆₅₀ = 2.90, the majority of the hCDD produced (75%) was processed precisely and secreted into the periplasmic space. These results demonstrate that E. coli cells are able to synthesize and secrete high levels of this human protein with a prokaryotic signal sequence.