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111.
Ross P Weinhouse H Aloni Y Michaeli D Weinberger-Ohana P Mayer R Braun S de Vroom E van der Marel GA van Boom JH Benziman M 《Nature》1987,325(6101):279-281
Cellulose is the most abundant renewable carbon resource on earth and is an indispensable raw material for the wood, paper, and textile industries. A model system to study the mechanism of cellulose biogenesis is the bacterium Acetobacter xylinum which produces pure cellulose as an extracellular product. It was from this organism that in vitro preparations which possessed high levels of cellulose synthase activity were first obtained in both membranous and soluble forms. We recently demonstrated that this activity is subject to a complex multi-component regulatory system, in which the synthase is directly affected by an unusual cyclic nucleotide activator enzymatically formed from GTP, and indirectly by a Ca (2+) -sensitive phosphodiesterase which degrades the activator. The cellulose synthase activator (CSA) has now been identified as bis-(3' 5')-cyclic diguanylic acid (5'G3'p5'G3'p) on the basis of mass spectroscopic data, nuclear magnetic resonance analysis and comparison with chemically synthesized material. We also report here on intermediary steps in the synthesis and degradation of this novel circular dinucleotide, which have been integrated into a model for the regulation of cellulose synthesis. 相似文献
112.
M. A. Livrea A. Bongiorno L. Tesoriere C. Nicotra A. Bono 《Cellular and molecular life sciences : CMLS》1987,43(5):582-586
Summary 11-cis retinaldehyde binding analysis was performed on a bovine retinal pigment epithelium preparation of cellular retinaldehyde binding protein (CRALBP), whose purity degree was estimated as 75%. Equilibrium binding studies were carried out measuring the replacement of tritium-labeled with unlabeled 11-cis retinaldehyde at 25°C. Analysis of the experimental data both by a direct curve-fitting procedure utilizing a non linear least square regression analysis and by a conventional Scatchard plot revealed a single non-interacting binding site with an apparent equilibrium constant of 0.9×10–7 M.A binding stoichiometry of approximately 1 mol of 11-cis retinaldehyde/mol of binding protein can be calculated from the experimental data. Competition studies carried out in the presence of unlabeled trans and cis isomers of Vitamin A derivatives confirm the high degree of specificity of the 11-cis retinaldehyde binding. 相似文献
113.
Chromosomal localization of human haemoglobin structural genes 总被引:15,自引:0,他引:15
114.
Division of chloroplasts in an artificial environment 总被引:9,自引:0,他引:9
115.
Stereochemistry of cooperative effects in haemoglobin 总被引:136,自引:0,他引:136
M F Perutz 《Nature》1970,228(5273):726-739
116.
X-linked gene for testicular feminization in the mouse 总被引:38,自引:0,他引:38
117.
Somatic translocation of antibody genes 总被引:36,自引:0,他引:36
118.
119.
RNA-DNA hybrids at the cytological level 总被引:37,自引:0,他引:37
120.