Structural and catalytic properties and homology modelling of the human nucleoside diphosphate kinase C, product of the DRnm23 gene
Structural and catalytic properties and homology modelling of the human nucleoside diphosphate kinase C, product of the DRnm23 gene
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DOI：
10.1046/j.1432-1327.2001.2076.doc.x
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发表时间：
2001-04-01
期刊：
影响因子：
--
通讯作者：
Lascu, I
中科院分区：
文献类型：
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作者：
Erent, M;Gonin, P;Lascu, I
人DRnm23基因是通过差异筛选从慢性髓系白血病-原始细胞危机原代细胞中获得的cDNA文库进行鉴定的。该基因的过度表达抑制了髓系前体细胞系的分化并诱导其凋亡。我们在细菌中过量生产了一种编码蛋白质的截短形式，缺少前17个N末端氨基酸。这种截短的蛋白质被称为二磷酸核苷(NDP)激酶C Delta。NDP激酶Ca与人类主要的NDP激酶A和B具有相似的动力学性质，但对尿素和热变性的稳定性明显更高。用大小排斥层析法分析尿素的变性，表明没有亚基解离的展开，而复性是通过折叠的单体发生的。蛋白质的稳定性主要取决于亚基之间的相互作用。根据NDP激酶B的晶体结构对NDP激酶C Delta的结构进行同源模拟，表明NDP激酶C Delta还有几个额外的稳定作用。两种酶的整体结构似乎是相同的，因为NDP激酶C Delta很容易与NDP激酶A形成混合六聚体。在体内可能观察到混合六聚体。
The human DRnm23 gene was identified by differential screening of a cDNA library obtained from chronic myeloid leukaemia-blast crisis primary cells. The over-expression of this gene inhibits differentiation and induces the apoptosis of myeloid precursor cell lines. We overproduced in bacteria a truncated form of the encoded protein lacking the first 17 N-terminal amino acids. This truncated protein was called nucleoside diphosphate (NDP) kinase C Delta. NDP kinase Ca had similar kinetic properties to the major human NDP kinases A and B, but was significantly more stable to denaturation by urea and heat. Analysis of denaturation by urea, using size exclusion chromatography, indicated unfolding without the dissociation of subunits, whereas renaturation occurred via a folded monomer. The stability of the protein depended primarily on subunit interactions. Homology modelling of the structure of NDP kinase C Delta, based on the crystal structure of NDP kinase B, indicated that NDP kinase C Delta had several additional stabilizing interactions. The overall structure of the two enzymes appears to be identical because NDP kinase C Delta readily formed mixed hexamers with NDP kinase A. It is possible that mixed hexamers can be observed in vivo.