铕(Ⅲ)对伴清蛋白溶液构象的影响  

Effect of Eu^(3+) on the Conformation of Apoovotransferrin

作　　者：李英奇[1,2] 周雪萍[2] 任学英[1] 段新娥[1] 

机构地区：[1]山西大学化学化工学院,太原030006 [2]山西大学分子科学研究所化学生物学与分子工程教育部重点实验室,太原030006

出　　处：《化学学报》2010年第10期1027-1031,共5页Acta Chimica Sinica

基　　金：山西省自然科学基金(No.2009011012-3);山西省自然科学青年基金(No.20051006)资助项目

摘　　要：用TNS疏水探针研究了脱铁伴清蛋白(apoOTf)和不同形式的铕伴清蛋白(EuN-OTf,Eu2-OTf)的表面疏水暴露程度,依次为apoOTf>EuN-OTf>Eu2-OTf,表明Eu3+与脱铁伴清蛋白N端结合引起蛋白构象变化大,与C端结合引起蛋白构象变化小.此外,由盐酸胍对3种蛋白变性实验,发现Eu3+与脱铁伴清蛋白的结合稳定了蛋白的结构,稳定性依次为apoOTf<EuN-OTf<Eu2-OTf.离子强度效应也充分表明3种蛋白内部疏水基团相互作用依apoOTf<EuN-OTf<Eu2-OTf顺序增大,稳定性也依次增大.本研究对进一步探讨Eu3+的生物效应提供理论依据.The extent of exposed hydrophobic patch on apoovotransferrin （apoOTf） and various species of europium（III） ovotransferrin （EuN-OTf and Eu2-OTf） were investigated using 2-p-toluidinylnaphtha-lene-6-sulfonate （TNS） as a fluorescence probe. The result showed that the extent of exposed hydrophobic patch on the protein was in turn：apoOTfEuN-OTfEu2-OTf. And apoovotransferrin （apoOTf） undergoes a large conformational change when Eu3＋ binds to the N-terminal site,but a small conformational change when the ion binds to the C-terminal site. In addition,the guanidine hydrochloride denaturation experiments on three kinds of protein showed that the binding of Eu3＋ to apoOTf led to a stable structure of OTf. Stability is in turn apoOTfEuN-OTfEu2-OTf. Ion strength effects demonstrate that internal hydrophobic interactions were enhanced in accordance with Eu2-OTfEuN-OTfapoOTf,thus stabilizing the protein conformation accordingly. Such information may afford our understanding of the biological effect on rare earth.

关 键 词：伴清蛋白 Eu3+ 构象变化 

分 类 号：Q51[生物学—生物化学]