GENETIC APPROACHES TO PROTEIN-NUCLEIC ACID INTERACTIONS

氨基酰基转移RNA合成酶在进化的早期就出现了 建立了遗传密码的规则，通过他们特定的 转移RNA的氨基酰化反应。这些酶被组织成两种 每班十种酵素。这两个班级似乎没有 彼此之间的历史关系。建议进行实验，以 研究和操纵第I类和第类的tRNA特异性 II酶。这些合成酶包括大肠杆菌丙氨酸、谷氨酰胺、 异亮氨酸和蛋氨酸tRNA合成酶和酿酒酵母谷氨酰胺 TRNA合成酶。最近的实验表明，氨基酸 受体螺旋是至少某些基因同一性的主要决定因素 TRNAs。功能性合成酶-tRNA受体螺旋接触将是 通过分析突变的酶来鉴定和操纵 根据受体螺旋相互作用中的特定变化而选择。 还将设计一种最低限度的氨基酰tRNA合成酶，并 受到功能活性的突变和选择。 更多的努力将针对tRNA识别的操作 通过引入尽可能少的氨基酸或核苷酸来实现特异性 替换，在某些情况下利用最近的x射线 晶体结构信息。

Aminoacyl transfer RNA synthetases arose early in evolution and established the rules of the genetic code through their specific aminoacylations of transfer RNAs. the enzymes are organized into two classes of ten enzymes each. These two classes appear to have no historical relationship to each other. Experiments are proposed to investigate and manipulate the tRNA specificity of class I and class II enzymes. These synthetases include E. coli alanine, glutamine, isoleucine and methionine tRNA synthetases, and S. cerevisiae glutamine tRNA synthetase. Recent experiments have shown that the amino acid acceptor helix is a major determinant of the identity of at least some tRNAs. Functional synthetase-tRNA acceptor helix contacts will be identified and manipulated through analysis of mutant enzymes which are selected for specific alterations in their acceptor helix interactions. A minimalist aminoacyl tRNA synthetase will also be designed and subjected to mutagenesis and selection for functional activity. Additional efforts will be directed at manipulations of tRNA recognition specificity by introducing the fewest possible amino acid or nucleotide substitutions, in some cases taking advantage of recent x-ray crystallographic structural information.