Macgregor R B, Weber G
Nature. 1986;319(6048):70-3. doi: 10.1038/319070a0.
Crystallographic studies of myoglobin have shown that the haem pocket is lined with nonpolar amino-acid residues. In order to estimate the true polarity of the interior of proteins, certain studies have used bound fluorophores, the spectroscopic properties of which reflect the polarity of their environment. These studies have most often used 1-amino-8-naphthalene sulphonate (ANS) as a probe, but a more suitable probe, in principle, is 6-propionyl 2-(N,N-dimethyl)aminonaphthalene (PRODAN). We have synthesized a molecule with the advantageous spectroscopic properties of PRODAN but with a higher affinity for apomyogloblin: 2'-(N,N-dimethyl)amino-6-naphthopyl-4-trans-cyclohexanoic acid (DANCA), and report here its use to determine the polarity of the myoglobin haem pocket. Our results show that the pocket is actually a polar environment, and the polarity can be accounted for by peptide amide dipoles.
肌红蛋白的晶体学研究表明，血红素口袋内衬有非极性氨基酸残基。为了估计蛋白质内部的真实极性，某些研究使用了结合荧光团，其光谱性质反映了它们所处环境的极性。这些研究最常使用1-氨基-8-萘磺酸盐（ANS）作为探针，但原则上更合适的探针是6-丙酰基-2-（N，N-二甲基）氨基萘（PRODAN）。我们合成了一种具有PRODAN有利光谱性质但对脱辅基肌红蛋白具有更高亲和力的分子：2'-（N，N-二甲基）氨基-6-萘基-4-反式环己酸（DANCA），并在此报告其用于确定肌红蛋白血红素口袋极性的用途。我们的结果表明，该口袋实际上是一个极性环境，其极性可以由肽酰胺偶极子来解释。
