Synthetic peptide analogs of skeletal troponin C: fluorescence studies of analogs of the low-affinity calcium-binding site II.
Synthetic peptide analogs of skeletal troponin C: fluorescence studies of analogs of the low-affinity calcium-binding site II.
复制标题
骨骼肌钙蛋白 C 的合成肽类似物：低亲和力钙结合位点 II 类似物的荧光研究。
DOI：
10.1016/0003-9861(83)90444-7
复制
发表时间：
1983
影响因子：
3.9
通讯作者：
Lenkinski,RE
中科院分区：
文献类型：
--
作者：
Kanellis,P;Yang,J;Cheung,HC;Lenkinski,RE
采用固相法合成了兔骨肌钙蛋白c Ca2+结合环的两个12残基肽，它们的序列与Ca2+特异性低亲和力结合位点II（残基63-74）的结合环相对应，但有两个氨基酸取代。在一种模拟中，ph -72被酪氨酸取代。另一方面Gly-66被丝氨酸取代，ph -72被酪氨酸取代。在加入Tb3+或大量过量的Ca2+后，肽的固有荧光增强。根据Tb3+发射常数在（2-3）× 105m−1范围内的增强，确定了Tb3+与肽结合的结合化学计量学为1。过量的Ca2+从Tb3+-肽复合物中取代Tb3+，从这些结果推断Ca2+结合的表观稳定性常数为500-700m−1。其中一个肽的初步质子核磁共振结果表明，La3+对几个残基的酰胺质子共振产生了相当大的扰动，包括3号位置的天冬氨酸、10号位置的酪氨酸和c端的两个谷氨酸。结果表明这些残基参与了阳离子配位。
Two 12-residue peptides were synthesized by the solid-phase method as structural analogs of a Ca2+-binding loop of rabbit skeletal troponin C. The sequence of the analogs corresponds to the binding loop of the Ca2+-specific low affinity binding site II (residues 63–74) but with two amino acid substitutions. In one analog, Phe-72 was replaced by tyrosine. In the other Gly-66 was substituted by serine and Phe-72 by tyrosine. The intrinsic fluorescence of the peptides was enhanced upon addition of Tb3+or large excess of Ca2+. From the enhancement of Tb3+emission association constants in the range (2–3) × 105m−1and a binding stoichiometry of 1 were determined for Tb3+binding to the peptides. Large excess of Ca2+displaced Tb3+from the Tb3+-peptide complexes and from these results apparent stability constants of 500–700m−1were deduced for Ca2+binding. Preliminary proton nuclear magnetic resonance results on one of the peptides indicated that La3+induced considerable perturbation of the amide proton resonances of several residues, including the aspartate at position 3, the tyrosine at position 10, and the two glutamates at the C-terminus. The results suggest involvement of these residues in cation coordination.