Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada.
Biophys J. 2011 Apr 6;100(7):1837-45. doi: 10.1016/j.bpj.2011.02.026.
Collagen fibrils are the main constituent of the extracellular matrix surrounding eukaryotic cells. Although the assembly and structure of collagen fibrils is well characterized, very little appears to be known about one of the key determinants of their biological function-namely, the physico-chemical properties of their surface. One way to obtain surface-sensitive structural and chemical data is to take advantage of the near-field nature of surface- and tip-enhanced Raman spectroscopy. Using Ag and Au nanoparticles bound to Collagen type-I fibrils, as well as tips coated with a thin layer of Ag, we obtained Raman spectra characteristic to the first layer of collagen molecules at the surface of the fibrils. The most frequent Raman peaks were attributed to aromatic residues such as phenylalanine and tyrosine. In several instances, we also observed Amide I bands with a full width at half-maximum of 10-30 cm(-1). The assignment of these Amide I band positions suggests the presence of 3(10)-helices as well as α- and β-sheets at the fibril's surface.
胶原原纤维是真核细胞周围细胞外基质的主要成分。尽管胶原原纤维的组装和结构已经得到很好的描述，但对于决定其生物学功能的关键因素之一——即其表面的物理化学性质，人们知之甚少。获得表面敏感结构和化学数据的一种方法是利用表面和尖端增强拉曼光谱的近场性质。我们利用结合在胶原 I 型原纤维上的 Ag 和 Au 纳米颗粒以及涂有一层薄 Ag 的尖端，获得了原纤维表面第一层胶原分子的特征拉曼光谱。最常见的拉曼峰归因于芳香族残基，如苯丙氨酸和酪氨酸。在几种情况下，我们还观察到半峰全宽为 10-30cm-1 的酰胺 I 带。这些酰胺 I 带位置的分配表明在原纤维表面存在 3(10) 螺旋以及 α-和 β-片层。
