Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8359320 | Protein Expression and Purification | 2018 | 6 Pages |
Abstract
Streptococcus pneumoniae is a major pathogen that causes life-threatening diseases, such as pneumonia, otitis media, bacteremia, and meningitis, worldwide and especially in young children and the elderly. Pneumococcal surface protein A (PspA) is a widely studied candidate protein vaccine that represents a promising replacement for current polysaccharide and polysaccharide-conjugate vaccines. In this study, we describe a simple method to produce PspA of clade 4 from an Escherichia coli expression system using hydroxylapatite and ion-exchange chromatography. Using this method, we successfully expressed soluble PspA4 in 10â¯L of autoinducing culture medium, with a wet-cell yield of 19â¯g/L and a final PspA4 concentration of 22.8â¯mg/L. Additionally, we improved PspA4 purity from 17% to 70% in a single step through the use of hydroxylapatite, resulting in acquisition of recombinant PspA4 (>95% purity) at a final yield of 43% from the starting cell-lysis solution. We subsequently verified the secondary structure molecular weight of recombinant PspA4 by circular dichroism and mass spectrometry, respectively. These results demonstrated a highly efficient method for mass producing PspA4 protein and that can also be applied for purification of PspA proteins from other clades.
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Authors
Hualong Xi, Jinfei Yu, Qing Sun, Jingcai Lu, Tiejun Gu, Xiaonan Guo, Bo Li, Xiaorui Chen, Kaixin Zhang, Wei Kong, Yongge Wu,