alpha-Hemolysin nanopore studies reveal strong interactions between biogenic polyamines and DNA hairpins

作者：Ding Yun; Fleming Aaron M; Burrows Cynthia J

来源：Microchimica Acta, 2016, 183(3): 973-979.

DOI：10.1007/s00604-015-1516-6

• alpha-Hemolysin
• DNA hairpin
• Spermine
• Spermidine
• Putrescine

The alpha-hemolysin (alpha-HL) nanopore is capable of analyzing DNA as it is electrophoretically driven through the pore. Respective current vs. time (i-t) traces depend on the DNA sequence, its secondary structures, or on the physical conditions of the analysis. The current study describes the analysis of a DNA hairpin with a 5'-extension by applying alpha-HL nanopores in the presence of the polyamines spermine (Spm), spermidine (Spd), and putrescine (Put) and revealed i-t traces characteristic of the DNA-polyamine complex. Voltage-dependent studies also revealed that the hairpin-Spm complex formed with excess Spm cannot be unzipped and translocated through the pores even if the voltage is increased to 180 mV. The DNA hairpin sample was titrated with Spm, Spd, or Put that showed a dose-dependent response in the characteristic event patterns for hairpins bound to Spm or Spd, but not for Put. Plots of the event types vs. counts were used to calculate binding constants for the Spm or Spd hairpin interactions. The titration also demonstrated that the event rate decreased similar to 10-fold on increasing the Spm or Spd concentrations from 0 to 4 mM. These observations impose practical limitations on the ability to use Spm or Spd for DNA studies with the alpha-HL nanopore.

• 出版日期2016-3