Structure and Physical Properties of RNA

描述（由申请人提供）：本申请寻求支持的主要活动是通过NMR和X射线晶体学确定生理学上重要的RNA的结构。最终目标是对所研究的RNA的生物学特性的化学理解。由于RNA在基因表达中起着关键作用，因此所寻求的知识对于我们理解对所有生物体（包括人类）至关重要的过程至关重要。两个具体的问题是要调查：在细菌中的核糖体蛋白质合成的调节，和真核生物中的核糖体RNA转录的假尿苷化。在细菌中，核糖体蛋白合成在翻译水平上通过依赖于特定核糖体蛋白与编码它们的mRNA内的序列之间的相互作用的机制进行反馈调节，其中许多是多顺反子的。两个直接相关的系统是spc操纵子/S8系统和L10操纵子。L10系统，但时间允许的话，将研究其他系统;例如alpha操纵子/L4系统。将尽可能精确地确定对每个核糖体蛋白操纵子的调节至关重要的mRNA序列。将获得这些RNA序列和与它们结合的核糖体蛋白之间形成的复合物的结构。基于这些结构提出的关于翻译抑制机制的假设，将在生物化学上得到检验。由于细菌调节核糖体蛋白质合成的机制与真核生物不同，因此可以想象，将揭示特异性抑制细菌生长的新方法。要研究的第二个问题是由boxH/ACA snoRNP系统负责在高等生物中的rRNA转录的pseudouridylating。这些snRNP的RNA组分被假定以在文献中没有先例的方式与rRNA转录物中的序列相互作用。将进行生化实验以确定假设的RNA/RNA相互作用是否可能，并将获得snoRNA的结构，有或没有适当的rRNA序列结合。

DESCRIPTION (provided by applicant): The principle activity for which this application seeks support is determination of the structures of physiologically important RNAs by NMR and X-ray crystallography. The ultimate objective is a chemical understanding of the biological properties of the RNAs studied. Since RNAs play critical roles in gene expression, the knowledge sought is fundamental to our understanding of processes vital to all organisms, including humans. Two specific problems are to be investigated: the regulation of ribosomal protein synthesis in bacteria, and the pseudouridylation of ribosomal RNA transcripts in eukaryotes. In bacteria, ribosomal protein synthesis is feed-back regulated at the translational level by mechanisms that depend on interactions between specific ribosomal proteins and sequences within the mRNAs that encode them, many of which are polycistronic. The two such systems of immediate concern are the spc operon/S8 system, and L10 operon./L10 system, but time permitting, others will be investigates; e.g. the alpha operon/L4 system. The mRNA sequence critical for the regulation of each ribosomal protein operon will be determined as precisely as possible. Structures will be obtained of the complexes that form between these RNA sequences and the ribosomal proteins that bind to them. Hypotheses about the mechanism of translational repression, formulated on the basis of those structures, will then be tested biochemically. Since bacteria regulate ribosomal protein synthesis by mechanisms unlike those used by eukaryotes, it is conceivable that new ways of specifically inhibiting bacterial growth will be revealed. The second problem to be investigated is posed by the boxH/ACA snoRNP system responsible for pseudouridylating rRNA transcripts in higher organisms. The RNA components of these snRNPs are postulated to interact with sequences in rRNA transcripts in a way that has no precedent in the literature. Biochemical experiments will be done to determine whether RNA/RNA interactions of the sort hypothesized are possible, and structures will be obtained for a snoRNA, with and without an appropriate rRNA sequence bound.