Zhou Zhiyong, Schnake Paul, Xiao Lihua, Lal Altaf A
Division of Parasitic Diseases, Centers for Disease Control and Prevention, 4770 Buford Highway, Chamblee, GA 30341, USA.
Protein Expr Purif. 2004 Mar;34(1):87-94. doi: 10.1016/j.pep.2003.11.006.
This study was conducted to compare the expression of three constructs of a multistage candidate vaccine (FALVAC-1) against Plasmodium falciparum in an Escherichia coli system: a synthetic gene with P. falciparum codons, a synthetic gene with optimized E. coli codons, and a synthetic gene with P. falciparum codons co-transformed with a RIG plasmid, which encodes three tRNAs (AG(A/G), ATA, GGA) that recognize rare E. coli codons. The expression of the protein increased at least threefold with codon optimization. The presence of the RIG plasmid in the co-transforming cells did not significantly increase the expression level of the gene with P. falciparum codons. The growth of cells transformed by the construct with P. falciparum codons was significantly slower than that of cells transformed by the construct with optimized E. coli codons after induction of protein expression with IPTG. The cells containing the non-codon optimized gene co-expressed with RIG plasmid had the slowest growth at all time points in culture. Thus, codon optimization significantly increases the yield of P. falciparum candidate vaccines in the E. coli expression system.
本研究旨在比较一种针对恶性疟原虫的多阶段候选疫苗（FALVAC-1）的三种构建体在大肠杆菌系统中的表达情况：一种具有恶性疟原虫密码子的合成基因、一种具有优化大肠杆菌密码子的合成基因，以及一种具有恶性疟原虫密码子且与编码三种识别大肠杆菌稀有密码子的tRNA（AG(A/G)、ATA、GGA）的RIG质粒共转化的合成基因。通过密码子优化，蛋白质表达至少增加了三倍。共转化细胞中RIG质粒的存在并未显著提高具有恶性疟原虫密码子的基因的表达水平。在用IPTG诱导蛋白质表达后，用具有恶性疟原虫密码子的构建体转化的细胞的生长明显慢于用具有优化大肠杆菌密码子的构建体转化的细胞。在培养的所有时间点，含有与RIG质粒共表达的非密码子优化基因的细胞生长最慢。因此，密码子优化显著提高了大肠杆菌表达系统中恶性疟原虫候选疫苗的产量。
