手性氨基酸对DNA链式聚合反应的影响

Effect of chiral amino acids on DNA chain polymerization

构成天然蛋白质的氨基酸为L构型,D构型氨基酸虽然不是构成蛋白质的基本结构单元,但许多植物、微生物甚至在人体中都有D-氨基酸的存在。DNA聚合酶链式反应广泛发生在生物体内及PCR实验中,首次探究手性氨基酸及其与金属离子协同条件下对Taq-DNA聚合酶催化下的DNA链式聚合反应的影响情况,为进一步研究手性氨基酸及金属离子对生物体的影响提供实验依据。变性聚丙烯酰胺凝胶电泳结果表明,酸性氨基酸对于DNA链式聚合反应有抑制作用,极性不带电荷氨基酸其L构型对引物延伸的抑制作用大于D构型氨基酸,而极性带正电荷的氨基酸D构型与L构型的作用则与其相反。在加入Na^(+)、K^(+)、Ca^(2+)等9种金属离子及手性氨基酸的实验当中,铝盐及锆盐溶液对PCR实验几乎完全抑制;镍、铜、钙对其影响次之。加入手性氨基酸金属络合物之后,其影响结果部分发生改变。

The amino acids that make up natural proteins are L-conformation.Although D-conformation amino acids are not the basic structural units of proteins,many plants,microorganisms,and even human bodies have D-amino acids.DNA polymerase chain reaction occurs widely in organisms and in PCR.In this paper,the effect of chiral amino acids and their coordination with metal ions on DNA chain reaction catalyzed by Taq-DNA polymerase was investigated for the first time.It provides experimental basis for further study of the effects of chiral amino acids and metal ions on organisms.Denaturing polyacrylamide gel electrophoresis showed that acidic amino acids had inhibitory effect on DNA chain polymerization,and the polar uncharged amino acids.The inhibition of primer extension by L configuration was greater than that of D configuration amino acids,whereas the D structure of polar positively charged amino acids was opposite to that of L configuration.In the experiments of adding 9 metal ions such as Na^(+),K^(+),Ca^(2+),and chiral amino acids,the PCR was almost inhibited by aluminium and zirconium salts,followed by nickel,copper and calcium.When chiral amino acid metal complexes were added,the influence of chiral amino acid metal complexes on the results was partly changed.