Cloning and expression of the L1 major capsid protein of the human papillomavirus type 16 in Escherichia coli

Human papillomavirus (HPV) constitutes the causative agent for genital warts and the vast majority of cervical, anogenital, and oropharyngeal cancers. Approximately 90% of patients with cervical cancer and genital warts are caused by nine types of HPV (6, 11, 16, 18, 31, 33, 45, 52, and 58). With some immunodominant neutralization epitopes and a self-assembly ability to form virus-like particles (VLPs), the major capsid protein L1 is one of the most important target proteins for HPV research. Previously, there were studies of L1 protein expression on hosts such as S.cerevisiae, insect cells, and P. pastoris,. with high cost and low yield, so we developed a high-level expression system of HPV16 L1 in Escherichia coli for the purpose of developing VLP to produce low-cost vaccines for developing countries. The first 4 amino acids of the N-terminal of the L1 gene were deleted to promote their expression level in E. coli. The truncated L1 gene of HPV serotype 16 was cloned in the expression vector and transformed into E. coli BL21(DE3). The recombinant L1 protein was successfully expressed in E. coli and purified. The suitable conditions for high-cell density fermentation of recombinant E. coli were determined.