酿酒酵母信号肽介导蛋白分泌的系统分析及优化

Protein secretion is a universal process in many organisms and is crucial for maintaining activities and functions of organisms. Recombinant protein production has become one of the most important industries in the field of the modern biotechnology. Secretory expression is preferred in recombinant protein production, as it assures proper translational modification of recombinant proteins and simplifies downstream purification processes. Signal peptide plays an important role for secretory proteins, which start the secretion process through ER by signal peptide leading. In this project, we will try to comprehensive analysis of signal peptides from the yeast Saccharomyces cerevisiae by integration of multi-level data, which includes the relative secretion levels of secretory proteins in medium, transcriptional levels, sequence and structure of signal peptides and secretory proteins. By a thorough global analysis, it is expected to reveal the relationship between signal peptides and secretion and figure out the core regions and general characterizations for efficient protein secretion. Based on this information, we will construct a signal peptide optimization model for design and improvement of signal peptides in efficient protein secretion. The findings from this project will expand our knowledge on fundamental characterizations of signal peptides and improve our understandings of underlying mechanisms of protein secretion. Furthermore, the outcomes of this project will provide useful information and general guidelines in selection and optimization of signal peptides for efficient protein secretion.

蛋白分泌广泛存在于生物体中，生物体的生命活动依赖其正常运作。重组蛋白生产已经成为现在生物技术领域的重要产业之一。通常以分泌表达形式来实现重组蛋白生产,来确保重组蛋白得到适当的翻译后修饰和简化下游纯化工艺。信号肽是介导蛋白分泌的重要元件，合适的信号肽对于蛋白分泌至关重要。本项目拟通过对酿酒酵母分泌型蛋白的相对蛋白分泌强度分析，结合信号肽、蛋白序列结构等信息，将多维度数据整合来系统性地揭示信号肽的特征与蛋白分泌的关联。确定高效介导蛋白分泌的信号肽核心模块，建立信号肽优化设计模型,并用于信号肽优化。本项目的开展实施，将有助于加深我们对于信号肽这一介导蛋白分泌的重要生物元件的认知，帮助理解蛋白分泌这一重要而又复杂的生命过程。此外，也为表达重组蛋白时，筛选优化信号肽序列提供参考分析依据，拓展可用于高效介导蛋白分泌表达的信号肽库。

信号肽是位于新生肽N端的一段氨基酸序列，起到介导蛋白分泌或转运定位的作用，对于维持细胞功能至关重要。信号肽也是工业生产分泌性蛋白的关键元件之一。目前，关于信号肽的运作规律及介导分泌的关键特征有待深入解析。本项目对模式生物酿酒酵母信号肽展开全基因组水平的系统分析，成功揭示出信号肽的若干关键特征，包括NHC区域性质、保守性基序、序列进化关联、密码子偏好性等。发现不同信号肽介导蛋白分泌时，对菌株生理代谢的影响有所差异。信号肽与辅助蛋白存在相互作用，其性质差异会带来不同的分泌效率。其中，信号肽NCW2在sec72敲除菌株中介导分泌淀粉酶的产量是对照组的10倍。通过本项目的开展实施，进一步阐明了信号肽的特征及功能，对于相关领域的基础研究及提升重组蛋白工业化生产效率具有一定的参考价值。