Elimination of the Chlamydomonas gene family that encodes the small subunit of ribulose-1,5-bisphosphate carboxylase oxygenase
Elimination of the Chlamydomonas gene family that encodes the small subunit of ribulose-1,5-bisphosphate carboxylase oxygenase
复制标题
DOI：
10.1073/pnas.93.24.13689
复制
发表时间：
1996-11-26
影响因子：
11.1
通讯作者：
Spreitzer, RJ
中科院分区：
文献类型：
--
作者：
Khrebtukova, I;Spreitzer, RJ
核酮糖-1，5-二磷酸羧化酶/加氧酶（Nucleulose-1，5-bisphosphate carboxylase/oxygenase，EC 4.1.1.39）是光合作用中催化CO2固定的关键酶。植物和绿色藻类的叶绿体全酶含有8个核编码的小亚基和8个叶绿体编码的大亚基。虽然已经了解了很多关于酶的活性位点，驻留在每个大亚基，它一直很难评估真核小亚基在全酶的功能和表达的作用。小亚基是由一个基因家族编码的，排除了遗传筛选或核转化方法来恢复小亚基突变体。在这项研究中，两个小亚基基因的绿色衣藻reinhardtii消除随机插入突变。光合作用缺陷缺失突变体可以与两种野生型小亚基基因中的任一种互补，或者与含有两者特征的嵌合基因互补，因此，任一种小亚基都足以进行全酶组装和功能。在缺乏小亚基的情况下，叶绿体编码的大亚基的表达似乎在翻译水平上受到抑制。
Ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) is the key photosynthetic enzyme that catalyzes the first step of CO2 fixation, The chloroplast-localized holoenzyme of plants and green algae contains eight nuclear-encoded small subunits and eight chloroplast-encoded large subunits. Although much has been learned about the enzyme active site that resides within each large subunit, it has been difficult to assess the role of eukaryotic small subunits in holoenzyme function and expression. Small subunits are coded by a family of genes, precluding genetic screening or nuclear transformation approaches for the recovery of small-subunit mutants, In this study, the two small-subunit genes of the green alga Chlamydomonas reinhardtii were eliminated during random insertional mutagenesis. The photosynthesis-deficient deletion mutant can be complemented with either of the two wild-type small-subunit genes or with a chimeric gene that contains features of both, Thus, either small subunit is sufficient for holoenzyme assembly and function. In the absence of small subunits, expression of chloroplast-encoded large subunits appears to be inhibited at the level of translation.