肺炎链球菌SP0498 Big、酵母SWI1 ARID和人SUV39H1 Chromo结构域的结构与功能研究

发布时间：2018-03-13 11:20

本文选题：NMR　切入点：肺炎链球菌　出处：《中国科学技术大学》2012年博士论文　论文类型：学位论文

【摘要】：本论文主要研究了肺炎链球菌表面蛋白SP0498Big结构域、酿酒酵母SWI1ARID结构域和人SUV39H1chromo结构域的结构和分子作用机制。 1.肺炎链球菌是人类急性呼吸道感染等严重疾病的致病菌。我们通过NMR的方法解析了肺炎链球菌表面蛋白SP0498中Big (bacterial immuno-globulin-like)结构域的溶液结构。SP0498Big结构域由8条p-链构成,呈桶状结构,与经典的免疫球蛋白结构域三明治状结构明显不同。有意思的是我们发现了SPO498Big结构域是一个Ca2+结合结构域,而且其结构与已知钙离子结合结构域不同,所以它的发现揭示了一种新的钙离子结合模块。此外,我们还鉴定出该结构域中可能参与钙离子结合的关键残基。我们首次从结构方面报道了Big结构域和钙离子的相互作用,这说明Big结构域可能在许多重要性、钙离子依赖的细胞过程,如细菌的致病过程中都具有重要作用。 2.SWI1是酿酒酵母中染色体重塑SWI/SNF的一个亚基。SWIl具有一个ARID (AT-rich interaction domain)结构域,该结构域具有潜在的DNA结合活性。我们通过NMR的方法解析了酿酒酵母中SWI1ARID结构域的溶液结构。该结构域由七个α螺旋组成,其中六个螺旋在ARID家族中保守。此外化学位移扰动实验表面了SWI1ARID结构域具有DNA结合活性。酿酒酵母SWI1ARID结构域与人SWI1ARID结构域类似,可以非特异地结合DNA。对SWI1ARID结构域溶液结构的解析和其非特异性结合DNA性质的探讨,使我们更深入地了解了ARID结构域家族的结构及其DNA结合特性,也为进一步解释酵母染色体重塑复合物SWI/SNF在基因转录调控方面的功能提供了帮助。 3SUV39H1是在人类中发现的第一个组蛋白赖氨酸甲基转移酶,它参与染色质的修饰和基因转录过程。SUV39H1在N端有一个chromodomain,该结构域参与甲基化赖氨酸的识别和SUV39H1在染色体上的定位。我们解析了人类SUV39H1chromodomain的晶体结构。SUV39H1chromodomain的结构与其它chromodomain相比,总体上是保守的。但不同的是,SUV39H1chromodomain在C端有一段较长的螺旋。此外,通过表面等离子共振实验我们发现该结构域可以特异性地识别H3K9me3。 SUV39H1chromodomain结构的解析,尤其是关于其对H3K9me3特异性识别的研究将有助于我们进一步了解SUV39H1蛋白在组蛋白的修饰、基因的沉默等重要生物学过程中的作用。
[Abstract]:In this paper, the structure and molecular mechanism of Streptococcus pneumoniae surface protein SP0498Big domain, Saccharomyces cerevisiae SWI1ARID domain and human SUV39H1chromo domain were studied. 1. Streptococcus pneumoniae is a pathogen of severe diseases such as acute respiratory tract infection in human. The solution structure of Big immuno-globulin-like domain of Streptococcus pneumoniae surface protein SP0498 was analyzed by NMR method. SP0498Big domain was composed of eight p- chains, which were barrel like structure. It is interesting to find that the SPO498Big domain is a Ca2 binding domain, and its structure is different from the known Ca ~ (2 +) binding domain. So its discovery reveals a new calcium binding module. In addition, we have identified the key residues in this domain that may be involved in calcium binding. We have reported for the first time the interaction between Big domain and calcium ion. This suggests that the Big domain may play an important role in many Ca2 +-dependent cellular processes such as bacterial pathogenicity. 2. SWI1 is a subunit of chromosome remodeling SWI/SNF in Saccharomyces cerevisiae. SWIl has a ARID AT-rich interaction domain. This domain has potential DNA binding activity. The solution structure of SWI1ARID domain in Saccharomyces cerevisiae was analyzed by NMR method. Six helices are conserved in the ARID family. In addition, the chemical shift perturbation experiments show that the SWI1ARID domain has DNA binding activity. The SWI1ARID domain of Saccharomyces cerevisiae is similar to the human SWI1ARID domain. The solution structure of SWI1ARID domain and its nonspecific binding properties of DNA can be unspecifically combined with DNA.Therefore, we have a better understanding of the structure of ARID domain family and its DNA binding properties. It also helps to explain the function of yeast chromosome remodeling complex (SWI/SNF) in gene transcription regulation. 3SUV39H1 is the first histone lysine methyltransferase found in humans. It is involved in chromatin modification and gene transcription. SUV39H1 has a chromodomainat the N terminal, and this domain is involved in the recognition of methylated lysine and the location of SUV39H1 on chromosome. We have analyzed the crystal structure of human SUV39H1chromodomain. But the difference is that the SUV39H1 chromodomain has a long helix at the C end. In addition, we find that the domain can specifically recognize the analysis of H3K9me3. SUV39H1chromodomain structure by surface plasmon resonance (SPR) experiment. In particular, the study on the specific recognition of H3K9me3 will help us to further understand the role of SUV39H1 protein in histone modification, gene silencing and other important biological processes.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：R378.14

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