克雷伯氏肺炎杆菌内抗亚碲酸盐蛋白质TerZ延伸环降低对钙离子亲合性（英文）  

The Extended Loop Reduces Ca^(2+)-Binding Affinity on the Tellurite Resistance Protein TerZ from Klebsiella penumoniae

作　　者：魏淑怡 潘韻如 曾天生 陈金榜[1] 

机构地区：[1]"中央研究院"生物医学科学研究所,台北11529

出　　处：《波谱学杂志》2015年第2期308-317,共10页Chinese Journal of Magnetic Resonance

基　　金："Academia Sinica and the National Science Council"(NSC103-2311-B-001-026-MY3)

摘　　要：亚碲酸盐是碲的一含氧阴离子,其对微生物具高度毒性.在许多的致病菌内已经鉴定出数个抗亚碲酸盐基因(terZABCDEF).之前,作者解出抗亚碲酸盐蛋白质TerD液体核磁共振结构并指出在细菌内TerD可能是一钙离子传感器.TerZ与TerD在序列上有40%相同性,其包括了一额外的9氨基酸片段L36-N44,并且显示出非常弱的钙离子亲合性.有趣的是,少了额外片段的TerZdel拥有与TerD可比较的钙离子亲合性.根据化学位移指数及同源模拟结果,此额外片段为一无二级结构且延伸的loop,可能扰乱钙离子结合位置的构形,同时也阻碍了钙离子接近其结合位置,因此大大降低钙离子亲合性.Tellurite （TeO32–）, an oxyanion of tellurium, is highly toxic to most microorganisms. Several tellurite resistance genes （terZABCDEF） have been identified in many pathogenic bacteria. Previously, we determined the NMR solution structure of the tellurite resistance protein TerD and suggested that TerD may function as a calcium sensor in bacteria. TerZ, which shares 40% sequence identity with TerD, contains an extra 9-residue segment of L36FGSIFGGN44 and exhibits much weaker Ca2＋-binding affinity. Interestingly, TerZdel in which the extra segment is deleted has comparable binding affinity to TerD. Based on chemical shift index and homology modeling results, it was revealed that the extra segment is unstructured and forms an extended loop, which may disturb the conformation of Ca2＋-binding sites and also prevent Ca2＋ from contacting its binding site, hence significantly reduce Ca2＋-binding affinity.

关 键 词：钙离子结合蛋白质 抗亚碲酸盐 钙离子传感器 化学位移指数 同源模拟 

分 类 号：O482.53[理学—固体物理]