The calcium-responsive P11-4 peptide was analyzed by intrinsic fluorescence emission spectrum, circular dichroism spectrum (CD), and atomic force microscope (AFM). Differential light scattering was used to monitor the nucleation growth rate of calcium phosphate nanocrystals in the absence or in the presence of P11-4. AFM was used to analyze the radial size (nm) of calcium phosphate nanocrystals formed in the absence or in the presence of P11-4, as well as to verify the spatial structure of P11-4 in the absence or in the presence of Ca2+.
The interaction of Ca2+ with the P11-4 (KD = 0.58 ± 0.06 mM) promotes the formation of β-sheet antiparallel structure, leads to its precipitation in saturated solutions of Ca/P = 1.67 and induces the formation of parallel large fibrils (0.6 - 1.5 µm). P11-4 organized the HAP nucleation by reducing both the growth rate and size variability of nanocrystals, analyzed by the F test (p < 0.0001, N = 30). P11-4 interacts (KD = 0.75 ± 0.06 μM) with the KGHRGFSGL motif present at the C-terminal collagen telopeptide domain. P11-4 also increased the amount of HAP and collagen in the MDPC-23 cells.
The presented data propose a mechanism that will help future clinical and/or basic research to better understand a molecule able to inhibit structural collagen loss and help the impaired tissue to remineralize.
方法:通过固有荧光发射光谱分析钙响应性P11-4肽,圆二色性光谱(CD),原子力显微镜(AFM)。在不存在或存在P11-4的情况下,使用差分光散射来监测磷酸钙纳米晶体的成核生长速率。AFM用于分析在不存在或存在P11-4的情况下形成的磷酸钙纳米晶体的径向尺寸(nm),以及验证在不存在或存在Ca2+的情况下P11-4的空间结构。
结果:Ca2与P11-4(KD=0.58±0.06mM)的相互作用促进了β-折叠反平行结构的形成,导致其在Ca/P=1.67的饱和溶液中沉淀,并诱导形成平行的大原纤(0.6-1.5µm)。P11-4通过降低纳米晶体的生长速率和尺寸可变性来组织HAP成核,通过F检验分析(p<0.0001,N=30)。P11-4与存在于C端胶原端肽结构域的KGHRGFSGL基序相互作用(KD=0.75±0.06μM)。P11-4还增加MDPC-23细胞中HAP和胶原的量。
结论:所提供的数据提出了一种机制,该机制将有助于未来的临床和/或基础研究更好地了解一种能够抑制结构性胶原蛋白损失并帮助受损组织再矿化的分子。