白喉毒素突变体蛋白(cross-reacting material 197, CRM197)是一种常用的多糖结合疫苗载体,其在大肠杆菌体系中往往以包涵体形式表达。为了改善通过包涵体复性来制备CRM197而导致的收率低、操作烦琐等不足,研究设计了一种基于SUMO标签...白喉毒素突变体蛋白(cross-reacting material 197, CRM197)是一种常用的多糖结合疫苗载体,其在大肠杆菌体系中往往以包涵体形式表达。为了改善通过包涵体复性来制备CRM197而导致的收率低、操作烦琐等不足,研究设计了一种基于SUMO标签串联的策略,改善重组CRM197的可溶性,同时使用Origami B (DE3)大肠杆菌宿主,成功使重组CRM197蛋白上清液可溶比例提高至95%以上。同时简化了CRM197蛋白的获取途径,经两步Ni亲和层析和一步酶切除去融合标签等手段建立了从破菌上清液中纯化CRM197的方法,获得纯度高于98%的CRM197且收率大于80%。通过圆二色光谱及荧光发射光谱分析等证实纯化所得CRM197空间结构折叠正确。抗原性ELISA实验结果表明所制得的CRM197蛋白与CRM197标准品蛋白抗原性相当。研究结果表明串联双SUMO标签对重组CRM197在大肠杆菌中高效、可溶表达具有促进作用,并建立了快速纯化体系,获得了具有较好免疫原性的CRM197蛋白,为改善重组蛋白在原核表达体系的可溶表达设计提供了新思路。展开更多
Despite the expansive applications of gas-phase unfolding techniques,the molecular mechanism for the solvent-free forced unfolding pathway which substrate multidomain proteins usually adopt remains elusive at the seco...Despite the expansive applications of gas-phase unfolding techniques,the molecular mechanism for the solvent-free forced unfolding pathway which substrate multidomain proteins usually adopt remains elusive at the secondary structure level.Herein,upon carefully selecting CRM_(197) as a therapeutically-relevant model system containing multiple secondary structure-separated domains,we systematically examine its solvent-free unfolding pathway.Further-more,utilizing the hybrid of noncovalent chemical probing with niacinamide and ion mobility-mass spectrometry-guided all-atom molecular dynamics simulations,we map a nearly complete unfolding atlas for the conjugate vaccine carrier protein CRM_(197) in a domain-and secondary structure-resolved manner.The totality of our data supports the preferential unfolding of the sheet-rich domain,indicating the dynamic transition from β-sheet toα-helix,and demonstrating that helix exhibit comparatively higher stability thanβ-sheets.We propose that this sheet-to-helix dynamic transition may be central to the gas-phase unfolding pathways of multidomain proteins,suggesting the need for systematic studies on additional multidomain protein systems.展开更多
文摘白喉毒素突变体蛋白(cross-reacting material 197, CRM197)是一种常用的多糖结合疫苗载体,其在大肠杆菌体系中往往以包涵体形式表达。为了改善通过包涵体复性来制备CRM197而导致的收率低、操作烦琐等不足,研究设计了一种基于SUMO标签串联的策略,改善重组CRM197的可溶性,同时使用Origami B (DE3)大肠杆菌宿主,成功使重组CRM197蛋白上清液可溶比例提高至95%以上。同时简化了CRM197蛋白的获取途径,经两步Ni亲和层析和一步酶切除去融合标签等手段建立了从破菌上清液中纯化CRM197的方法,获得纯度高于98%的CRM197且收率大于80%。通过圆二色光谱及荧光发射光谱分析等证实纯化所得CRM197空间结构折叠正确。抗原性ELISA实验结果表明所制得的CRM197蛋白与CRM197标准品蛋白抗原性相当。研究结果表明串联双SUMO标签对重组CRM197在大肠杆菌中高效、可溶表达具有促进作用,并建立了快速纯化体系,获得了具有较好免疫原性的CRM197蛋白,为改善重组蛋白在原核表达体系的可溶表达设计提供了新思路。
基金support by the National Key R&D Program of China(No.2022YFA1305200,to GL)National Natural Science Foundation of China(No.22104064 to GL,No.22173020 to JL)the US National Institute of Mental Health(No.R01MH122742,to CJW)for financial and instrumental support.
文摘Despite the expansive applications of gas-phase unfolding techniques,the molecular mechanism for the solvent-free forced unfolding pathway which substrate multidomain proteins usually adopt remains elusive at the secondary structure level.Herein,upon carefully selecting CRM_(197) as a therapeutically-relevant model system containing multiple secondary structure-separated domains,we systematically examine its solvent-free unfolding pathway.Further-more,utilizing the hybrid of noncovalent chemical probing with niacinamide and ion mobility-mass spectrometry-guided all-atom molecular dynamics simulations,we map a nearly complete unfolding atlas for the conjugate vaccine carrier protein CRM_(197) in a domain-and secondary structure-resolved manner.The totality of our data supports the preferential unfolding of the sheet-rich domain,indicating the dynamic transition from β-sheet toα-helix,and demonstrating that helix exhibit comparatively higher stability thanβ-sheets.We propose that this sheet-to-helix dynamic transition may be central to the gas-phase unfolding pathways of multidomain proteins,suggesting the need for systematic studies on additional multidomain protein systems.
