精胺酸及其衍生物在螺旋中的側鏈作用力

Abstract

螺旋結構是重要的蛋白質二級結構之一,並且對其生物活性有重 要影響。 離子對做用力是其中一種影響蛋白質摺疊的作用力,並且對蛋白質的螺旋結構有重要影響。 離胺酸和精胺酸在離子對作用力中扮 演重要的角色,並且能連結其他分子。 精胺酸側鏈較離胺酸側鏈長一個亞甲基。 精胺酸以及較短側鏈的精胺酸類似物對螺旋內的離子作用力 有重要影響。 因此,我利用圓二色光譜儀檢測含有精胺酸以及較短 側鏈的精胺酸類似物的胜鏈, 得到了下列螺旋程度的趨勢: GluArg4 > GluArg5 > AspArg5 > GluArg3 > AspArg4 > GluAgb4 > AspAgb4 > GluAgp3 = AspAgp3 並且藉由基於Lifson-Roig理論的nesting block方法 求取其離子對作用力; 同時量測這些胜鏈在不同 pH 環境下,螺旋程 度以及離子對作用力的差異。

Helix is an important secondary structure, and is crucial for many biological activities. Ion pair interaction is one of the most important forces for protein folding, and plays an important role in helix structure stabilization. Lysine (Lys) and arginine (Arg) are important players in ion paring, and serves to bind peptides with other molecules. The side chain of Arg is an atom long than Lys. Various Arg analogues with shorter side chain may also play a role in intra helical ion pair interaction. Thus, Arg and various Arg analog peptides as determined by circular dichroism spectroscopy. The trend for the helical content of these peptides is GluArg4 > GluArg5 > AspArg5 > GluArg3 > AspArg4 > GluAgb4 > AspAgb4 > GluAgp3 = AspAgp3. Ion pair interaction energy via the nesting block method with modified Lifson- Roig theory. The helical content of the peptides as measured at different pH values to obtain more detailed information about the ion pairing interactions.