Verrelli B C, Eanes W F
Department of Ecology and Evolution, State University of New York, Stony Brook, New York 11794-5245, USA.
Genetics. 2001 Sep;159(1):201-10. doi: 10.1093/genetics/159.1.201.
Earlier studies of the common PGM allozymes in Drosophila melanogaster reported no in vitro activity differences. However, our study of nucleotide variation observed that PGM allozymes are a heterogeneous mixture of amino acid polymorphisms. In this study, we analyze 10 PGM protein haplotypes with respect to PGM activity, thermostability, and adult glycogen content. We find a twofold difference in activity among PGM protein haplotypes that is associated with a threefold difference in glycogen content. The latitudinal clines for several Pgm amino acid polymorphisms show that high PGM activity, and apparently higher flux to glycogen synthesis, parallel the low activity clines at G6PD for reduced pentose shunt flux in northern latitudes. This suggests that amino acid polymorphism is under selection at this branch point and may be favored for increased metabolic storage associated with stress resistance and adaptation to temperate regions.
早期对黑腹果蝇常见磷酸葡萄糖变位酶（PGM）同工酶的研究报告称，其体外活性没有差异。然而，我们对核苷酸变异的研究发现，PGM同工酶是氨基酸多态性的异质混合物。在本研究中，我们分析了10种PGM蛋白单倍型的PGM活性、热稳定性和成虫糖原含量。我们发现PGM蛋白单倍型之间的活性存在两倍差异，这与糖原含量的三倍差异相关。几种Pgm氨基酸多态性的纬度渐变表明，高PGM活性以及明显更高的糖原合成通量，与北纬地区葡萄糖-6-磷酸脱氢酶（G6PD）低活性渐变平行，以降低戊糖磷酸途径通量。这表明在这个分支点上氨基酸多态性受到选择，并且可能有利于增加与抗逆性和适应温带地区相关的代谢储存。
