波谱学杂志 ›› 2015, Vol. 32 ›› Issue (2): 308-317.doi: 10.11938/cjmr20150213

• 研究论文 • 上一篇    下一篇

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

魏淑怡,潘韻如,曾天生,陈金榜*   

  1. 生物医学科学研究所,台湾 台北 11529
  • 收稿日期:2015-03-02 修回日期:2015-05-08 出版日期:2015-06-05 发布日期:2015-06-05
  • 作者简介:*通讯联系人:陈金榜,电话:+886-2-27899162, E-mail: bmchinp@ibms.sinica.tw.
  • 基金资助:


The Extended Loop Reduces Ca2+-Binding Affinity on the Tellurite Resistance Protein TerZ from Klebsiella penumoniae

WEI Shu-yi,PAN Yun-ru,TSENG Tien-sheng,CHEN Chin-pan*   

  1. Institute of Biomedical Sciences, Taipei 11529, China
  • Received:2015-03-02 Revised:2015-05-08 Online:2015-06-05 Published:2015-06-05
  • About author:*Corresponding author: CHEN Chin-pan, Tel: +886-2-27899162, E-mail: bmchinp@ibms.sinica.tw.
  • Supported by:


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.

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

Abstract:

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.

Key words: Ca2+-binding protein, tellurite resistance, calcium sensor, chemical shift index, homology modeling

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