Deoxycytidine kinase and deoxyguanosine kinase of Lactobacillus acidophilus R-26 are colinear products of a single gene.
Deoxycytidine kinase and deoxyguanosine kinase of Lactobacillus acidophilus R-26 are colinear products of a single gene.
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嗜酸乳杆菌R-26的脱氧胞苷激酶和脱氧鸟苷激酶是单个基因的共线产物。
DOI：
10.1073/pnas.93.25.14385
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发表时间：
1996
影响因子：
11.1
通讯作者：
Ives,DH
中科院分区：
文献类型：
--
作者：
Ma,N;Ikeda,S;Guo,S;Fieno,A;Park,I;Grimme,S;Ikeda,T;Ives,DH
嗜酸乳杆菌R-26生长所需的四种脱氧核苷激酶中有三种以异二聚体形式存在，对脱氧腺苷（dAK）和脱氧胞苷（dCK）或脱氧鸟苷（dGK）具有特异性。然而，只有两个串联的基因，dak/dgk，被发现，并只表达dAK/dGK在transformedEscherichia coli。对跨越天然dCK亚基63%的肽段进行测序，发现除了dCK缺少残基2和3（dCK是M··IVL; dGK是·TVIVL）之外，其序列与从dgk（开始为MTVIVL···）推导的序列相同。此外，质谱表明天然dCK和dGK亚基在针对前三个残基调整的质量上是相同的。此外，天然酶具有相同的等电pH值，表明带电残基的数量相等。为了使E. colito表达具有天然dCK序列的肽，从串联基因的dck部分删除密码子2和3，导致具有天然dAK/dCK的特异性和调节特性的蛋白质的表达，包括脱氧胞苷或dCTP（不是脱氧鸟苷或dGTP）对dAK活性的异嗜性刺激和dATP和dCTP对各自活性的终产物抑制。亚克隆正常和突变dGK分别产生同源二聚体dGK和dCK。dCK同源二聚体与人dCK非常相似，对脱氧胞苷具有低Km值，能够在高得多的Km值下磷酸化脱氧腺苷和脱氧鸟苷，并通过dCTP抑制终产物。因此，两种不同的和特异的酶显然是从一个单一的乳酸杆菌基因。这种现象在体内发生的机制尚待阐明。
Three of the four deoxynucleoside kinases required for growth ofLactobacillus acidophilusR-26 exist as heterodimeric pairs specific for deoxyadenosine (dAK) and deoxycytidine (dCK) or dAK and deoxyguanosine (dGK). However, only two tandem genes,dak/dgk, are found, and are expressed only as dAK/dGK in transformedEscherichia coli. Sequencing peptides spanning 63% of the native dCK subunit revealed a sequence identical to that deduced fromdgk(beginning MTVIVL···), except that dCK lacks residues 2 and 3 (dCK is M··IVL; dGK is ·TVIVL). Also, mass spectrometry indicates that native dCK and dGK subunits are identical in mass adjusted for the first three residues. Furthermore, the native enzymes have identical isoelectric pH values, indicating an equal number of charged residues. To enableE. colito express peptide having the native dCK sequence, codons 2 and 3 were deleted from thedgkportion of the tandem genes, resulting in expression of protein having the specificities and regulatory properties of native dAK/dCK, including heterotropic stimulation of dAK activity by deoxycytidine or dCTP (not deoxyguanosine or dGTP) and end-product inhibition of the respective activities by dATP and dCTP. Subcloning normal and mutantdgkyielded homodimeric dGK and dCK, respectively. The dCK homodimer strongly resembles human dCK, with a lowKmfor deoxycytidine, the ability to phosphorylate deoxyadenosine and deoxyguanosine at much higherKmvalues, and end-product inhibition by dCTP. Thus two distinct and specific enzymes evidently are derived from a singleLactobacillusgene. The mechanism by which this occursin vivohas yet to be elucidated.
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嗜酸乳杆菌 R-26 的异二聚脱氧鸟苷激酶/脱氧腺苷激酶：脱氧腺苷激酶亚基的异向激活涉及有限的蛋白水解和亲和标记。
影响因子：
2.9
作者：
Ikeda,S;Ives,DH
通讯作者：
Ives,DH
嗜酸乳杆菌单体激酶上脱氧鸟苷和脱氧腺苷磷酸化的不同位点。
影响因子：
2.9
作者：
R. Chakravarty;S. Ikeda;D. H. Ives
通讯作者：
D. H. Ives
影响因子：
2.9
作者：
KIM, JM;RUZICKA, F;FREY, PA
通讯作者：
FREY, PA
一种用于清洗放射化学酶测定中使用的离子交换纸盘的新系统。
影响因子：
2.9
作者：
D. H. Ives
通讯作者：
D. H. Ives
DOI：
10.1073/pnas.88.4.1531
发表时间：
1991-02-01
影响因子：
11.1
作者：
CHOTTINER, EG;SHEWACH, DS;MITCHELL, BS
通讯作者：
MITCHELL, BS