多肽与花粉钙调素的相互作用及对细胞功能的影响

研究了在Ca²⁺存在下,丹磺酰标记的花粉钙调素(D-pCaM)与合成的多肽相互作用的规律.研究结果表明,被研究的绝大多数多肽能与D-pCaM结合而形成复合物,使D-pCaM的荧光光谱发生变化.用荧光法测定了这些复合物的解离常数K_d,其中肽BP-13的Kd值为4.0nmol/L,是与pCaM结合能力最强的一个多肽.除证明了多肽的疏水性,预测二级结构形成倾向和链长对其与pCaM结合能力有影响外,还发现用D-丙氨酸取代肽链中的Gly或L-丙氨酸后,可改变肽对pCaM的亲和性,这为提高多肽与钙调素的亲和力提供了一条改进的途径.我们的研究还可以定性地说明不同来源CaM性质相似又有差异,反映了它们的高度保守性和变异性.同时还展示了所研究的多肽对细胞信息传导过程的影响,为研究CaM对细胞功能调节的作用机制和建立pCaM拮抗肽的活性筛选模型提供了思路.

Interaction of Peptides with Pollen Camodulin and Their Effects on Cellular Functions

The interaction between dansyl-labeled pollen calmodulin(D-pCaM) and buckwheat pollen peptide analogs was studied in the presence of Ca²⁺. Most peptides in our research can associate with D-pCaMand form peptide-pCaMcomplexes, which changed the fluorescence spectra of D-pCaM. The dissociation constants K_dfor these complexes were determined using fluorescence titration. Peptide BP-13, AMALALKKTGNH₂, had the smallest K_dvalue 4.0 nmol/L, demonstrating the highest affinity for pCaM. In addition to studying the influence of hydrophobicity, propensity of secondary structure and chain length on these peptides abilities to bind pCaM, we have also found that Gly/L-Ala→D-Ala substitution in peptide chains caused great changes in their affinity for pCaM. These results suggest a potentially useful approach to improving the binding ability of peptidic antagonist to CaM. Furthermore, our data provided evidence on the dissimilarity of different CaMs although they have highly-conserved structures. Aprimary study was carried out on the effects of CaM-binding peptides on cellular signal transduction, cell proliferation and growth, showing the participation of CaMin this important cellular life process.