Yumoto N, Murase S, Hattori T, Yamamoto H, Tatsu Y, Yoshikawa S
Government Industrial Research Institute, Osaka, Japan.
Biochem Biophys Res Commun. 1993 Nov 15;196(3):1490-5. doi: 10.1006/bbrc.1993.2420.
To elucidate the alpha-helix-stabilizing effect of amino acids at the helical ends, we prepared analogs of C-terminal fragments of neuropeptide Y (NPY) containing an alpha-helical part. The helix-stabilizing tendency of N-terminal amino acid in NPY (12-36) was found to be as follows: Thr > Ser > Gly > Gln > Cys > Asn > Asp > Val > Phe > Glu > Lys > Tyr > Ala = Trp > His > Arg, suggesting the importance of end capping. The capping effect was not evident when N-termini in NPY (11-36) and NPY (13-36) were replaced. Under the same conditions as those for the receptor binding, [Thr12]NPY (12-36) had about 4-fold higher alpha-helix content than [Arg12]NPY (12-36). However, there was no apparent relationship between the helix content and binding affinity to the Y2 receptor.
为阐明氨基酸在螺旋末端对α-螺旋的稳定作用，我们制备了含有α-螺旋部分的神经肽Y（NPY）C末端片段类似物。发现NPY（12 - 36）中N末端氨基酸的螺旋稳定趋势如下：苏氨酸>丝氨酸>甘氨酸>谷氨酰胺>半胱氨酸>天冬酰胺>天冬氨酸>缬氨酸>苯丙氨酸>谷氨酸>赖氨酸>酪氨酸>丙氨酸 = 色氨酸>组氨酸>精氨酸，这表明末端封端的重要性。当NPY（11 - 36）和NPY（13 - 36）中的N末端被替换时，封端效应不明显。在与受体结合相同的条件下，[苏氨酸12]NPY（12 - 36）的α-螺旋含量比[精氨酸12]NPY（12 - 36）高约4倍。然而，螺旋含量与对Y2受体的结合亲和力之间没有明显关系。
