Ramesh V, Bradbury J H
Int J Pept Protein Res. 1986 Aug;28(2):146-53.
1H n.m.r. studies at 270 MHz were made of the transformation of 2 Zn insulin hexamer to 4 Zn hexamer produced by the addition of anions (thiocyanate ion). Four separate H2 histidine resonances were observed for the B5 and B10 histidines in 2 Zn hexamer at pH 7 and 9 and four separate resonances also occurred in the 4 Zn hexamer. The observation of these resonances and others from phenylalanine, tyrosine and leucine residues showed that the 2 Zn to 4 Zn transformation probably occurred in solution in a similar manner to that observed in the crystal. Furthermore as occurred in the crystal, it was found that in solution the transformation was reversible (on removal of thiocyanate) and that 2 Cd insulin was unable to undergo the transformation. Des-Phe-Bl-insulin did not undergo the transformation. Addition of SCN- to Zn-free insulin (mainly dimer) produced only a small transformation, consistent with the idea that Zn2+ promotes formation of hexamer from dimer but probably does not otherwise affect the transformation.
在270兆赫下进行了1H核磁共振研究，以观察通过添加阴离子（硫氰酸根离子）使2锌胰岛素六聚体向4锌六聚体的转变。在pH值为7和9时，观察到2锌六聚体中B5和B10组氨酸的四个不同的H2组氨酸共振峰，4锌六聚体中也出现了四个不同的共振峰。对这些共振峰以及苯丙氨酸、酪氨酸和亮氨酸残基的其他共振峰的观察表明，2锌向4锌的转变在溶液中的发生方式可能与在晶体中观察到的相似。此外，正如在晶体中所发生的那样，发现在溶液中这种转变是可逆的（去除硫氰酸盐后），并且2镉胰岛素不能发生这种转变。去苯丙氨酸-B1-胰岛素不会发生这种转变。向无锌胰岛素（主要是二聚体）中添加硫氰根离子仅产生了很小的转变，这与锌离子促进二聚体形成六聚体但可能不会以其他方式影响转变的观点一致。
