Oligonucleotide conjugates of Eu(III) tetraazamacrocycles with pendent alcohol and amide groups promote sequence-specific RNA cleavage.
Oligonucleotide conjugates of Eu(III) tetraazamacrocycles with pendent alcohol and amide groups promote sequence-specific RNA cleavage.
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Eu(III) 四氮杂大环与侧链醇和酰胺基团的寡核苷酸缀合物可促进序列特异性 RNA 切割。
DOI：
10.1007/s007750050011
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Morrow,JR
中科院分区：
文献类型：
--
作者：
Huang,L;Chappell,LL;Iranzo,O;Baker,BF;Morrow,JR
赤藓红蛋白是从硫酸盐还原菌脱硫弧菌中分离的非血红素铁二聚体蛋白。每个单体具有一个类似于红氧还蛋白的单核铁中心和一个类似于血红蛋白或核糖核苷酸还原酶的双核金属中心。用分子置换技术解出了“孤立态”分子和一个铀酰重原子衍生物的1.88 π X射线结构。由此产生的模型的天然“作为分离的”分子，包括164个水分子，已被细化，得到一个finalRfactor为0.197（Rfree=0.255）。该结构具有与先前发现的红红素相同的一般蛋白质折叠、结构域结构和二聚体相互作用[1，2]，但在金属中心也具有一些有趣的未检测到的差异。蛋白质结构的精确模型在残基78和79之间具有acispeptide。Fe-Cys 4中心具有以前未检测到的强第七N-H... S氢键除了六个N-H... S键通常存在于红氧还蛋白中。双核金属中心具有六配位Fe原子和四配位Zn原子。每种金属由GluXXHis多肽链段配位。锌原子结合在一个网站上发现的结构中的二铁红蛋白明显不同。铀酰衍生物的差电子密度显示出一个极大的峰，它邻近并取代了Zn原子，这表明这个特定的位点能够结合其他原子。这种特征/能力可能会引起一些归因于该分子的令人困惑的活性。
Rubrerythrin is a non-heme iron dimeric protein isolated from the sulfate-reducing bacteriumDesulfovibrio vulgaris. Each monomer has one mononuclear iron center similar to rubredoxin and one dinuclear metal center similar to hemerythrin or ribonucleotide reductase. The 1.88 Å X-ray structure of the “as isolated” molecule and a uranyl heavy atom derivative have been solved by molecular replacement techniques. The resulting model of the native “as isolated” molecule, including 164 water molecules, has been refined giving a finalRfactor of 0.197 (Rfree=0.255). The structure has the same general protein fold, domain structure, and dimeric interactions as previously found for rubrerythrin [1, 2], but it also has some interesting undetected differences at the metal centers. The refined model of the protein structure has acispeptide between residues 78 and 79. The Fe-Cys4center has a previously undetected strong seventh N-H...S hydrogen bond in addition to the six N-H...S bonds usually found in rubredoxin. The dinuclear metal center has a hexacoordinate Fe atom and a tetracoordinate Zn atom. Each metal is coordinated by a GluXXHis polypeptide chain segment. The Zn atom binds at a site distinctly different from that found in the structure of a diiron rubrerythrin. Difference electron density for the uranyl derivative shows an extremely large peak adjacent to and replacing the Zn atom, indicating that this particular site is capable of binding other atoms. This feature/ability may give rise to some of the confusing activities ascribed to this molecule.