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DNA-histidine complex formation in isoelectric histidine buffers
N C Stellwagen1, C Gelfi, P G Righetti
1Department of Biochemistry, University of Iowa, Iowa City 52242, USA.
Journal of Chromatography. A
|May 18, 1999
Summary
DNA forms complexes with histidine, affecting its movement in solution. Adding neutral salts can disrupt these complexes, with effects varying by DNA size and salt type.
Area of Science:
- Biophysical Chemistry
- Molecular Biology
- Electrophoresis
Background:
- Histidine is a DNA-binding amino acid.
- Electrophoretic mobility is a key property for analyzing DNA in solution.
- Understanding DNA-electrolyte interactions is crucial for various biological and chemical applications.
Purpose of the Study:
- To investigate the formation and characteristics of DNA-histidine complexes.
- To determine the influence of neutral salts on these complexes.
- To explore the role of electrostatic interactions in DNA-histidine complex stabilization.
Main Methods:
- Free solution electrophoresis was used to measure the electrophoretic mobility of DNA molecules.
- Experiments were conducted in isoelectric histidine buffers with and without added electrolytes.
- Electropherograms were analyzed for peak distortion and splitting to assess complex formation.
Main Results:
- Extensive DNA-histidine complex formation was observed in isoelectric histidine buffer, indicated by distorted and split electropherogram peaks.
- Addition of low-molecular-mass neutral salts decreased or eliminated peak distortion and splitting.
- The effectiveness of salts in disrupting complexes depended on DNA molecular mass, salt concentration, and salt type.
Conclusions:
- DNA-histidine complex formation is significant in isoelectric histidine buffers.
- Electrostatic interactions play a key role in stabilizing DNA-histidine complexes.
- Neutral salts can modulate DNA-histidine complex stability, with salt-dependent and DNA-dependent effects.