Carpenter S D, Charite J, Eggers B, Vermaas W F
Department of Botany, Arizona State University, Tempe 85287-1601.
FEBS Lett. 1990 Jan 15;260(1):135-7. doi: 10.1016/0014-5793(90)80085-w.
The translation start codon for psbC, the gene encoding CP43, a chlorophyll-binding protein of photosystem II, has been identified for the cyanobacterium Synechosystis sp. PCC 6803 using site-directed mutagenesis. An AUG codon, about 50 bases upstream from the end of psbD-I had previously been assumed to be the translation start site of psbC. However, the fact that the AUG codon is not present in psbC from several other organisms, whereas a GUG codon 14 bases upstream from the end of psbD-I is strictly conserved suggests that CP43 translation starts at the latter codon. Mutation of GUG, but not of AUG, led to a loss of CP43 and photoautotrophic growth, indicating that the GUG codon is the sole initiation site for translation of the CP43 protein in Synechocystis sp. PCC 6803.
利用定点诱变技术，已确定了集胞藻6803（Synechosystis sp. PCC 6803）中编码光系统II叶绿素结合蛋白CP43的基因psbC的翻译起始密码子。此前一直认为，位于psbD-I末端上游约50个碱基处的一个AUG密码子是psbC的翻译起始位点。然而，其他几种生物的psbC中不存在该AUG密码子，而psbD-I末端上游14个碱基处的一个GUG密码子却严格保守，这表明CP43的翻译起始于后一个密码子。对GUG而非AUG进行突变会导致CP43缺失和光合自养生长丧失，这表明GUG密码子是集胞藻6803中CP43蛋白翻译的唯一起始位点。
