Zhang Xiaobin, Wang Ying, Li Hui, Zhang Wanqi, Wu Di, Mi Huaifeng
Biochemical Section of State Key Laboratory of Functional Polymer Materials for Adsorption and Separation, Chemical School of Nankai University, 300071 Tianjin, PR China.
FEBS Lett. 2004 Feb 13;559(1-3):57-60. doi: 10.1016/S0014-5793(04)00024-9.
FK506 binding protein 23 from mouse (mFKBP23) is a peptidyl-prolyl cis-trans isomerase (PPIase) from the endoplasmic reticulum (ER), which consists of an N-terminal PPIase domain and a C-terminal domain with Ca(2+) binding sites. The assay of adsorption from ER extract with glutathione S-transferase-mFKBP23 attached to glutathione-Sepharose 4B shows that mFKBP23 binds to mouse immunoglobulin binding protein (mBiP). The same assay with the recombinant proteins of the N- and C-termini of mFKBP23 shows that the binding of the C-terminus is Ca(2+)-dependent and the switch point is between 2 and 3 mM. By high concentration of Ca(2+) this binding cannot be detected. Furthermore, the Ca(2+)-regulated binding of mFKBP23 and mBiP in ER can be detected by means of co-immunoprecipitation.
来自小鼠的FK506结合蛋白23（mFKBP23）是一种来自内质网（ER）的肽基脯氨酰顺反异构酶（PPIase），它由一个N端PPIase结构域和一个带有Ca(2+)结合位点的C端结构域组成。用附着在谷胱甘肽-琼脂糖4B上的谷胱甘肽S-转移酶-mFKBP23从内质网提取物中进行吸附测定，结果表明mFKBP23与小鼠免疫球蛋白结合蛋白（mBiP）结合。对mFKBP23的N端和C端重组蛋白进行相同测定，结果表明C端的结合是Ca(2+)依赖性的，转换点在2至3 mM之间。通过高浓度的Ca(2+)无法检测到这种结合。此外，内质网中mFKBP23和mBiP的Ca(2+)调节结合可以通过共免疫沉淀检测到。
