DETERMINATION OF THE SECONDARY STRUCTURE OF PROTEINS FROM THE AMIDE-I BAND OF THE LASER RAMAN-SPECTRUM
DETERMINATION OF THE SECONDARY STRUCTURE OF PROTEINS FROM THE AMIDE-I BAND OF THE LASER RAMAN-SPECTRUM
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DOI：
10.1016/0022-2836(81)90127-3
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发表时间：
1981-01-01
影响因子：
5.6
通讯作者：
DUNKER, AK
中科院分区：
文献类型：
--
作者：
WILLIAMS, RW;DUNKER, AK
蛋白质激光拉曼光谱中的酰胺I带被分解成6个组分，每个组分代表不同类型二级结构中的残基。这些结构类型有有序或双氢键螺旋(据信位于螺旋片段的中心)、无序或单氢键螺旋(据信位于螺旋片段的末端)、反平行β折叠、平行β折叠、反向旋转和未定义。用超定方程组的最小二乘解，从10个已知二级结构的蛋白质和多聚L赖氨酸的溶剂减去拉曼光谱中计算了代表每种残基构象100%的拉曼光谱。然后将这些参考光谱的线性组合与这些蛋白质和其他蛋白质的实验酰胺I光谱进行拟合，以估计这些构象中残基的比例。统计检验表明，双氢键螺旋和单氢键螺旋之间的区别以及平行和反平行β-折叠之间的区别是显著的。这些研究还没有完成对随机结构和话轮的区分。17个蛋白质样品的X射线和拉曼结构估测结果之间的绝对差异一般为6%。从蛋白质的酰胺I谱可以得到对二级结构的详细和相当准确的估计。
The amide I band in the laser Raman spectrum of proteins was resolved into 6 components, each representing residues in a different type of secondary structure. These structure types are ordered or bihydrogen-bonded helix (believed to be located in the center of helical segments), disordered or monohydrogen-bonded helix (believed to be located at the ends of helical segments), antiparallel beta sheet, parallel beta sheet, reverse turn and undefined. The Raman spectrum representing 100% of each type of residue conformation was computed from the solvent-subtracted Raman spectra of 10 proteins with known secondary structure, plus poly-L-lysine using a least-squares solution of the overdetermined system of equations. Linear combinations of these reference spectra were then fitted to the experimental amide I spectra of these and other proteins to estimate the fractions of residues in these conformations. Statistical tests suggest that the discrimination between bihydrogen-bonded helix and monohydrogen-bonded helix is significant as is the discrimination between parallel and antiparallel .beta.-sheet. The discrimination between random structure and turns has not yet been accomplished by these studies. The absolute difference between X-ray and Raman estimates of structure for 17 protein samples is generally < 6%. Detailed and reasonably accurate estimates of secondary structure can be derived from the amide I spectra of proteins.