Bonitz S G, Berlani R, Coruzzi G, Li M, Macino G, Nobrega F G, Nobrega M P, Thalenfeld B E, Tzagoloff A
Proc Natl Acad Sci U S A. 1980 Jun;77(6):3167-70. doi: 10.1073/pnas.77.6.3167.
The mitochondrial genome of Saccharomyces cerevisiae codes for 24 tRNAs. The nucleotide sequences of the tRNA genes suggest a unique set of rules that govern the decoding of the mitochondrial genetic code. The four codons of unmixed fmilies are recognized by single tRNAs that always have a U in the wobble position of the anticodon. The codons of the mixed families are read by two different tRNAs. Codons terminating in a C or U are recognized by tRNAs with a G and codons terminating in a G or A are recognized by tRNAs with a U in the corresponding positions of the anticodons. There are two exceptions to these rules. In the AUN family for isoleucine and methionine, the isoleucine tRNA has a G and the methionine tRNA has a C in the wobble position. The tRNA for the arginine CGN family also has an A in the wobble position of the anticodon. It is of interest that the CGN codons have not been found in the mitochondrial genes sequenced to date. The simplified decoding system of yeast mitochondria allows all the codons to be recognized by only 24 tRNAs.
酿酒酵母的线粒体基因组编码24种tRNA。tRNA基因的核苷酸序列表明了一套独特的规则，这些规则支配着线粒体遗传密码的解码。单一tRNA识别未混合家族的四个密码子，这些tRNA在反密码子的摆动位置总是有一个U。混合家族的密码子由两种不同的tRNA读取。以C或U结尾的密码子由反密码子相应位置带有G的tRNA识别，以G或A结尾的密码子由反密码子相应位置带有U的tRNA识别。这些规则有两个例外。在异亮氨酸和甲硫氨酸的AUN家族中，异亮氨酸tRNA在摆动位置有一个G，甲硫氨酸tRNA在摆动位置有一个C。精氨酸CGN家族的tRNA在反密码子的摆动位置也有一个A。有趣的是，迄今为止在线粒体基因序列中尚未发现CGN密码子。酵母线粒体简化的解码系统允许仅24种tRNA识别所有密码子。
