Chromium (III)-nucleotide complexes as probes of the guanosine 5'-triphosphate-induced microtubule assembly.
Chromium (III)-nucleotide complexes as probes of the guanosine 5'-triphosphate-induced microtubule assembly.
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铬 (III)-核苷酸复合物作为鸟苷 5-三磷酸诱导的微管组装的探针。
DOI：
10.1016/0003-9861(78)90086-3
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发表时间：
1978
影响因子：
3.9
通讯作者：
D. Purich
中科院分区：
文献类型：
--
作者：
R. MacNeal;D. Purich
铬(III)GTP被证明促进微管的组装，这些微管与使用镁GTP组装的微管没有区别。使用铬(III)GTP的组装速度比使用镁GTP的组装速度要快。Cr(III)GTP的作用不是由于GTP与Cr(III)GTP的解离所致。用[8-14C]Cr(III)GTP组装的微管每摩尔微管蛋白二聚体结合0.55摩尔的14C标记。这与相同条件下的[8-14C]GTP结合相当。~(14)C标记的分布为55%的铬(III)GTP、30%的GDP和15%的Cr(III)GDP。使用铬(III)GTP组装的微管具有显著的抗钙解聚能力，但在冷条件下很容易解聚。讨论了钙诱导解聚的两种可能模型。没有发现铬(III)-三磷酸腺苷和铬(III)GDP都不支持组装。铬(III)-三磷酸腺苷抑制ATP和UTP诱导的组装，但不抑制GTP或ITP诱导的组装。这是从核苷二磷酸的角度讨论的，假设核苷-5‘-三磷酸盐将磷酰基穿梭到GDP上，从而间接支持组装。
Cr(III)GTP is shown to promote assembly of microtubules that are indistinguishable from those assembled using MgGTP. The rate of assembly using Cr(III)GTP is faster than the rate of assembly using MgGTP. The action of Cr(III)GTP is not due to dissociation of GTP from Cr(III)GTP. Microtubules assembled using [8-14C]Cr(III)GTP are shown to bind 0.55 mol of14C label per mol of tubulin dimer. This is comparable to [8-14C]GTP binding under identical conditions. The distribution of14C label is shown to be 55% Cr(III)GTP, 30% GDP, and 15% Cr(III)GDP. Microtubules assembled using Cr(III)GTP have marked resistance to calcium depolymerization but are readily depolymerized by exposure to cold. Two possible models for calcium-induced depolymerization are discussed. Neither Cr(III)ATP nor Cr(III)GDP was found to support assembly. Cr(III)ATP was found to inhibit ATP- and UTP-induced assembly but not GTP- or ITP-induced assembly. This is discussed in terms of the nucleoside diphosphokinase postulated to shuttle phosphoryl groups from nucleoside-5′-triphosphates to GDP, thereby supporting assembly indirectly.