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A Pt(II) complex containing three 1-methylcytosine ligands (C), [Pt(NH3)C3] (CIO4)2· H2], has been prepared starting with cis-Pt(NH3)2Cl2, and its crystal structure has been determined. The title compound represents a model of a hypothetical interaction of cis.Pt(II) with three biomolecules which proceeds via an intermediate monochloro complex, cis-[Pt(NH3)2CCl]Cl, and loss of ammonia from this compound. [Pt(NH3)C3](ClO4)2·H2O crystallizes in space group P21/c (No. 14) with a = 15.296(3), b = 4.666(3), c = 14.025(2) Å, β = 122.61(1)° and has 4 formula units in the unit cell. Data were collected with use of a Syntex P21 diffractometer and MoKα radiation. The crystal structure was determined by standard methods and refined to R1 = 0.043 and R2 = 0.056 based on 2925 independent reflections. The compound contains the three 1-methylcytosine ligands bound through N(3) with the three ligands almost perpendicular to the Pt coordination plane. The two C ligands trans to each other have identical orientations with respect to the platinum square plane whereas the cytosine trans to NH3 has the opposite orientation. Bond lengths and angles are normal. 相似文献
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Intracellular distribution of DNA topoisomerase I in fibroblasts from patients with Fanconi's anaemia 总被引:3,自引:0,他引:3
Benhard Auer Hans-Peter Vosberg Ursula Buhre Helmut Klocker Monica Hirsch-Kauffmann Manfred Schweiger 《Human genetics》1982,61(4):369-371
Summary The activity of DNA topoisomerase I (DNA nicking-closing enzyme) was analysed in cytoplasmic and nuclear extracts of six independently derived Fanconi and four normal fibroblast cell lines. In all experiments the total cellular activity was predominantly found in the nuclear extracts (88–100%). In addition, a minor proportion of the enzyme (up to 12%) was randomly present in some of the cytoplasmic fractions of both Fanconi and normal fibroblasts. These results indicate that Fanconi's anaemia is probably not due to or accompanied by a maldistribution of topoisomerase I between nuclei and cytoplasm. 相似文献
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