Conformations in the Solid State and Solubility Properties of Protected Homooligopeptides of Glycine and β-Alanine
作者:Mitsuaki Narita、Masamitsu Doi、Koji Kudo、Yusuke Terauchi
DOI:10.1246/bcsj.59.3553
日期:1986.11
IR spectroscopic conformational analyses of Boc–Glyn–OBzl (n=3–7) and Boc–(β-Ala)n–OBzl (n=3–8) were performed in the solid state, suggesting the occurrence of the β-sheet structure in the higher oligomers (n=5–8). Solubility data indicate that insolubilities of Boc–Glyn–OBzl and Boc–(β-Ala)n–OBzl in high-polar solvents begin at hexa- and heptapeptide levels, respectively. Insolubility of protected homooligopeptides of Gly and β-Ala was estimated to be caused by β-sheet aggregation. The high potential for the β-sheet formation of Boc–Glyn–OBzl and Boc–(β-Ala)n–OBzl (n≥5) could clearly be attributed to the great freedom of the peptide backbone dihedral angles of each of the Gly and β-Ala residues in the β-sheet structure. The implications of a replacement of a few Gly residues with β-Ala residues in surface regions of proteins are also discussed.
在固态下对Boc–Glyn–OBzl(n=3–7)和Boc–(β-Ala)n–OBzl(n=3–8)进行了红外光谱构象分析,结果表明较高聚体(n=5–8)中存在β-折叠结构。溶解度数据显示,Boc–Glyn–OBzl和Boc–(β-Ala)n–OBzl在高度极性溶剂中的不溶性分别从六肽和七肽水平开始。保护性同聚肽Gly和β-Ala的不溶性估计是由β-折叠聚集引起的。Boc–Glyn–OBzl和Boc–(β-Ala)n–OBzl(n≥5)形成β-折叠结构的高潜力可以明显归因于β-折叠结构中每个Gly和β-Ala残基肽骨架二面角的大自由度。还讨论了蛋白质表面区域中少量Gly残基被β-Ala残基替代的意义。