Ca2+ and Mg2+ bind tetracycline with distinct stoichiometries and linked deprotonation

被引：99

作者：

Jin, Lihua ^{[1
]}

Amaya-Mazo, Xylenia ^{[1
]}

Apel, Matthew E. ^{[1
]}

Sankisa, Sudha S. ^{[1
]}

Johnson, Elissa ^{[1
]}

Zbyszynska, Monika A. ^{[1
]}

Han, Alexander ^{[1
]}

机构：

[1] De Paul Univ, Dept Chem, Chicago, IL 60614 USA

来源：

BIOPHYSICAL CHEMISTRY | 2007年 / 128卷 / 2-3期

基金：

美国国家科学基金会;

关键词：

isothermal titration calorimetry; tetracycline metal ion interaction and stoichiometry; linked deprotonation; intrinsic binding enthalpy; conformational change;

D O I：

10.1016/j.bpc.2007.04.005

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Tetracycline depends on divalent metal ions for its biological function, but its multiple ionization states, conformations, and tautomers at varying solution conditions complicate its ion-binding equilibria, and the stoichiometry of the biologically relevant Ca2+ or Mg2+ complexes has not been clear. Isothermal titration calorimetry was used in the present work to study Ca2+ and Mg2+ binding to tetracycline. The two metal ions bind with distinct stoichiometries, one Ca2+ per tetracycline and one Mg2+ per two tetracyclines, and with differing dependence on solution conditions, indicating that these two ions bind TC differently. An endothermic process accompanies ion binding that is proposed to reflect conformational changes in tetracycline. The results identify conditions that limit the distribution of species and may facilitate structural study. (c) 2007 Elsevier B.V All rights reserved.

引用

页码：185 / 196

页数：12

共 44 条

[1] Evaluation of linked protonation effects in protein binding reactions using isothermal titration calorimetry [J].