Photosynthetic Genes and Their Expression

纯化了光系统II配合物的一个低分子质量亚基，并测定了其部分氨基酸序列。发现其基因是由叶绿体基因组编码的，该基因被命名为psnK。通过体外转录和翻译系统合成了外源性光系统II蛋白的前体33-kDa和23-kDa蛋白，并利用基质加工酶活性测定了它们的第一加工位点。在大肠杆菌中表达了一种蓝藻外源33-kDa蛋白的基因，并确定了该蛋白在大肠杆菌中表达后的加工位点。测定了Rubisco小亚基和大亚基基因（rbcS和rbcL）光诱导转录的作用谱。结果表明，光敏色素Pfr可以诱导红细胞的转录，光敏色素Pfr也可以诱导rbcL的转录，但另外还有一种蓝光吸收色素。揭示了质体DNA甲基化调控高等植物非光合细胞中rbcL的转录。从一种光合细菌vinosum中克隆了一个新的Rubisco基因，发现该基因在细菌中表达，而不是先前克隆的基因。克隆了玉米PEP羧化酶的cDNA和基因组DNA，并测定了它们的核苷酸序列。克隆了天门冬氨酸氨基酰基转移酶cDNA，并测定了其核苷酸序列。克隆了烟草光系统I复合体一个15.5 kDa亚基的cDNA，并测定了其核苷酸序列。

A low-molecular-mass subunit of photosystem II complex was purified and its partial amino acid seguence was determined. It was found that its gene is encoded by the choloroplast genome, and the gene was termed as psnK. Precursors of the extrinsic photosystem II proteins, 33-kDa and 23-kDa proteins were synthesized from their cDNAs by in vitro transcription and translation system, and their first precessing sited were determined with the stromal processing enzyme activity. The gene for the extrinsic 33-kDa protein of a cyanobacterium was expressed in E. coli, and the processing site of this protein after the expression in E. coli was determined.2. Action spectra for the light-induced transcription of the Rubisco small subunit and large subunit genes (rbcS and rbcL) were measured. the result suggests that the transcription of rbcS is induced by phytochrome Pfr and that the transcription of rbcL is induced also by phytochrome Pfr, but in addition, by a blue light-absorbing pigment. It was disclosed that methylation of plastid DNA regulates the transcription of rbcL in the non-photosynthetic cells of higher plants. A new Rubisco gene was cloned from a photosynthetic bacterium Chromatium vinosum, and it was found that this gene, but not the previously cloned gene, is expressed in the bacterium.3. The cDNA and genomic DNA for maize PEP carboxylase were cloned and their nucleotide sequences were determined. The cDNA for aspartate aminoacyltransferase from Panicum maximam was cloned and its nucleotide sequence was determined.4. The cDNA for a 15.5 kDa subunit of tobacco photosystem I complex was cloned and its nucleotide sequence was determined.