Stein J L, Haygood M, Felbeck H
Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla 92093.
Proc Natl Acad Sci U S A. 1990 Nov;87(22):8850-4. doi: 10.1073/pnas.87.22.8850.
The gene coding for ribulose-1,5-bisphosphate carboxylase [RuBisCO; 3-phospho-D-glycerate carboxy-lyase (dimerizing), EC 4.1.1.39] was cloned from a sulfur-oxidizing chemoautotrophic bacterium that resides as an endosymbiont within the gill tissues of Alvinoconcha hessleri, a gastropod inhabiting deep-sea hydrothermal vents. Nucleotide sequence analysis of the cloned fragment demonstrated that the genes encoding the large (RbcL) and small (RbcS) subunits of the symbiont RuBisCO were organized similarly to the RuBisCO operons of free-living photo- and chemoautotrophic prokaryotes. The symbiont rbcL gene shared the highest degree of nucleotide sequence identity with the cyanobacterium Anabaena (69%) while the rbcS nucleotide sequence shared 61% identity with that of the green alga Chlamydomonas reinhardtii. Comparison with a 153-nucleotide partial rbcL sequence from a symbiont of the bivalve Solemya reidi indicated that the two symbiont sequences shared 85% sequence identity at the nucleotide level and 93% at the amino acid level, suggesting a relatively recent common origin. Escherichia coli transformed with a plasmid carrying the RuBisCO operon of the gastropod symbiont in the proper orientation for transcription from the plasmid lac promoter expressed catalytically active RuBisCO. The presence of enzyme activity suggests the proper assembly of the subunits of this deep-sea RuBisCO into the holoenzyme.
编码核酮糖-1,5-二磷酸羧化酶[RuBisCO；3-磷酸-D-甘油酸羧基裂解酶（二聚化），EC 4.1.1.39]的基因，是从一种硫氧化化能自养细菌中克隆得到的，这种细菌作为内共生体存在于赫氏深海蛤（Alvinoconcha hessleri）的鳃组织中，赫氏深海蛤是一种栖息于深海热液喷口的腹足纲动物。对克隆片段的核苷酸序列分析表明，编码共生体RuBisCO大亚基（RbcL）和小亚基（RbcS）的基因，其组织方式与自由生活的光合和化能自养原核生物的RuBisCO操纵子相似。共生体rbcL基因与蓝藻鱼腥藻（Anabaena）的核苷酸序列同一性最高（69%），而rbcS核苷酸序列与莱茵衣藻（Chlamydomonas reinhardtii）的同一性为61%。与双壳类里氏潜泥蛤（Solemya reidi）共生体的153个核苷酸的rbcL部分序列进行比较表明，这两个共生体序列在核苷酸水平上的序列同一性为85%，在氨基酸水平上为93%，这表明它们有相对较近的共同起源。用携带腹足纲动物共生体RuBisCO操纵子的质粒进行转化，该质粒以正确的方向从质粒lac启动子转录，从而使大肠杆菌表达出具有催化活性的RuBisCO。酶活性的存在表明这种深海RuBisCO的亚基正确组装成了全酶。
