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标题：Choline kinase II is present only in nodules that synthesize stable peribacteroid membranes
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作者：Robert B. Mellor ; Tove M. I. E. Christensen ; Dietrich Werner 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1986
卷号：83
期号：3
页码：659-663
DOI：10.1073/pnas.83.3.659
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Host-cell cytoplasm from soybean plants infected with the peribacteroid membrane (PBM)-building Rhizobium japonicum strain 61-A-101 (effective, N2-fixing) had much higher choline kinase activity than cytoplasm from either uninfected tissue or tissue infected with the non-PBM-building (ineffective, non-N2-fixing) strain 61-A-24. Ion-exchange chromatography showed that both types of nodule and root tissue possessed constitutive choline kinase I activity that had a Km for choline of {approx}150 {micro}M. The nodules of the effective symbiosis had another activity, choline kinase II (Km = 81 {micro}M). Nondenaturing and NaDodSO4 electrophoresis revealed no multimeric subunit structure of the two enzyme forms but did show the molecular sizes for choline kinase I, 58-59 kDa, and choline kinase II, 60 kDa. Choline kinase I and II and pI values of 8.1 and 8.5, respectively, and two-dimensional gel electrophoresis of whole cytoplasm from control and infected tissue showed a spot corresponding to choline kinase II only in the case of the effective symbiosis, whereas both tissue types had spots corresponding to choline kinase I. Choline kinase II is presumed to be encoded by the plant as neither free-living nor symbiotic (bacteroid) forms of the prokaryote showed any choline kinase activity.
关键词：nodulin-like protein ; Rhizobium japonicum ; Glycine max ; symbiosis