Bredell Helba, Smith Jacques J, Görgens Johann F, van Zyl Willem H
Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa.
Department of Process Engineering, Stellenbosch University, Stellenbosch, South Africa.
Yeast. 2018 Sep;35(9):519-529. doi: 10.1002/yea.3318. Epub 2018 May 24.
Cervical cancer is ranked the fourth most common cancer in women worldwide. Despite two prophylactic vaccines being commercially available, they are unaffordable for most women in developing countries. We compared the optimized expression of monomers of the unique HPV type 16 L1-L2 chimeric protein (SAF) in two yeast strains of Pichia pastoris, KM71 (Mut ) and GS115 (Mut ), with Hansenula polymorpha NCYC 495 to determine the preferred host in bioreactors. SAF was uniquely created by replacing the h4 helix of the HPV-16 capsid L1 protein with an L2 peptide. Two different feeding strategies in fed-batch cultures of P. pastoris Mut were evaluated: a predetermined feed rate vs. feeding based on the oxygen consumption by maintaining constant dissolved oxygen levels (DO stat). All cultures showed a significant increase in biomass when methanol was fed using the DO stat method. In P. pastoris the SAF concentrations were higher in the Mut strains than in the Mut strains. However, H. polymorpha produced the highest level of SAF at 132.10 mg L culture while P. pastoris Mut only produced 23.61 mg L . H. polymorpha showed greater potential for the expression of HPV-16 L1/L2 chimeric proteins despite the track record of P. pastoris as a high-level producer of heterologous proteins.
宫颈癌是全球女性中第四大常见癌症。尽管有两种预防性疫苗已投入商业使用，但对于发展中国家的大多数女性来说，它们仍难以负担。我们将人乳头瘤病毒16型（HPV-16）独特的L1-L2嵌合蛋白（SAF）单体在两种巴斯德毕赤酵母菌株KM71（Mut⁻）和GS115（Mut⁺）中的优化表达与多形汉逊酵母NCYC 495进行比较，以确定生物反应器中的首选宿主。SAF是通过用L2肽替换HPV-16衣壳L1蛋白的h4螺旋而独特创建的。评估了巴斯德毕赤酵母Mut⁺分批补料培养中的两种不同补料策略：预定补料速率与基于维持恒定溶解氧水平（溶解氧稳态）的氧气消耗进行补料。当使用溶解氧稳态方法加入甲醇时，所有培养物的生物量均显著增加。在巴斯德毕赤酵母中，Mut⁺菌株中的SAF浓度高于Mut⁻菌株。然而，多形汉逊酵母在132.10 mg/L培养物中产生的SAF水平最高，而巴斯德毕赤酵母Mut⁺仅产生23.61 mg/L。尽管巴斯德毕赤酵母作为异源蛋白的高产宿主有良好记录，但多形汉逊酵母在表达HPV-16 L1/L2嵌合蛋白方面显示出更大的潜力。
