Anderle G, Mendelsohn R
Biophys J. 1987 Jul;52(1):69-74. doi: 10.1016/S0006-3495(87)83189-2.
Fourier transform-infrared (FT-IR) spectra are reported for the amide III spectral region of the native and thermally denatured forms of chymotrypsinogen, ribonuclease, bovine serum albumin, and lysozyme. Chymotrypsinogen denatures into structures containing substantial contributions from beta-sheets, while lysozyme and bovine serum albumin show increased amounts of random-coil forms. The changes observed for ribonuclease are quite small. Bovine serum albumin shows at least six bands in the 1,260-1,320 cm-1 region which undergo large intensity changes upon thermal denaturation, and hence are assignable to alpha-helical amide III modes. The large number of observed bands suggests that slight variations in helical geometry, symmetry, or interactions result in changed amide III frequencies, so that simple correlations between narrow frequency ranges and secondary structures may not be applicable for this mode. A widened frequency range is suggested as diagnostic for helical structures.
报道了胰凝乳蛋白酶原、核糖核酸酶、牛血清白蛋白和溶菌酶天然形式和热变性形式的酰胺III光谱区域的傅里叶变换红外（FT-IR）光谱。胰凝乳蛋白酶原变性为含有大量β-折叠贡献的结构，而溶菌酶和牛血清白蛋白显示出增加的无规卷曲形式的量。核糖核酸酶观察到的变化非常小。牛血清白蛋白在1260 - 1320 cm-1区域至少有六个条带，这些条带在热变性时经历大的强度变化，因此可归因于α-螺旋酰胺III模式。观察到的大量条带表明，螺旋几何形状、对称性或相互作用的轻微变化会导致酰胺III频率改变，因此窄频率范围与二级结构之间的简单相关性可能不适用于此模式。建议拓宽频率范围作为螺旋结构的诊断依据。
