Expression of Synthetic Human Lysozyme Gene in Escherichia coli

Abstract

A 418 base pair DNA duplex consisting of a gene for human lysozyme with a synthetic ribosome binding site of E.coli was assembled by stepwise ligation of 56 chemically synthesized oligodeoxyribonucleotides. The synthesized gene was expressed under the control of the lambda pRpL promoter and the gene product accumulated as several percent of the total cellular proteins in E. coli. The expressed product existed as insoluble and biologically inactive aggregates in the cells, but the biological activity was regenerated by solubilization and renaturation of the aggregated protein. The results of the N-terminal amino acid sequence analysis of the product showed the human lysozyme synthesized in E. coli has an additional methionine residue at the N-terminal of the mature human lysozyme due to the translational initiation codon of E. coli.