Howell S H, Heizmann P, Gelvin S, Walker L L
Department of Biology, University of California, San Diego, La Jolla, California 92093.
Plant Physiol. 1977 Mar;59(3):464-70. doi: 10.1104/pp.59.3.464.
Properties of the mRNA coding for the large subunit of ribulose-1,5-bisphosphate carboxylase from Chlamydomonas reinhardi were determined. Large subunit synthesis, directed by RNA from partially purified whole cell extracts, was detected by specific immunoprecipitation of polypeptide products synthesized in a heterologous translation system derived from Escherichia coli. Large subunit synthesis showed sharp RNA concentration dependence in an E. coli translation system, and at optimal RNA concentrations, immunoprecipitable large subunit synthesis accounted for 2% of the total incorporation. Large subunit messenger activity sedimented at 12 to 14S on nondenaturing sucrose gradients and did not bind to oligo(dT)-cellulose suggesting the mRNA is not polyadenylated. The immunoprecipitable products translated in vitro are not complete polypeptide chains, but are smaller peptides identifiable as large subunit fragments by tryptic fingerprint analysis. No immunoprecipitable product was obtained when similar RNA fractions were tested in a wheat germ translation system.
对莱茵衣藻中1,5-二磷酸核酮糖羧化酶大亚基的mRNA特性进行了测定。通过对源自大肠杆菌的异源翻译系统中合成的多肽产物进行特异性免疫沉淀，检测了部分纯化的全细胞提取物中的RNA所指导的大亚基合成。在大肠杆菌翻译系统中，大亚基合成表现出对RNA浓度的强烈依赖性，在最佳RNA浓度下，可免疫沉淀的大亚基合成占总掺入量的2%。大亚基信使活性在非变性蔗糖梯度上沉降于12至14S，且不与寡聚（dT）-纤维素结合，这表明该mRNA没有聚腺苷酸化。体外翻译的可免疫沉淀产物不是完整的多肽链，而是较小的肽段，通过胰蛋白酶指纹图谱分析可鉴定为大亚基片段。当在麦胚翻译系统中测试类似的RNA组分时，未获得可免疫沉淀的产物。
