title: Noncovalent interaction of G-quadruplex DNA with acridine at low concentration monitored by MALDI-TOF mass spectrometry.
abstract: The telomeric G-rich single-stranded DNA d(T(2)G(8)) can adopt in vitro G-quadruplex structure, even at low DNA concentration. Studies on stability of telomeric structures, has gained importance recently as the molecules, which can stabilize quadruplex structure, can inhibit cancer progression. In this study, G-quadruplex structure is formed by 1.0 mM NH(4)(I) ion. Stability of G-quadruplex complex is studied on interaction with acridine using CD and MALDI-TOF mass spectrometry. MALDI-TOF mass spectrometric experiments were carried out mainly to observe the noncovalent drug-DNA interactions at low concentration. From MALDI-TOF spectrum, it is identified that three ammonium ions are required for the formation of G-quadruplex structure and to provide stability to NH(4)(I)-G-quadruplex complex. With MALDI-TOF it is evident that two acridine molecules interact with NH(4)(I) G-quadruplex complex. CD studies, shows that stability of NH(4)(I) G-quadruplex, decreases and conformation change takes place on interaction with acridine. Interaction with drug reduces mostly due to transformation of G-quadruplex complex to single stranded DNA.
authors: Centre for Cellular and Molecular Biology, Hyderabad, India. nagesh@ccmb.res.in
authors: Narayana
authors: N
authors: Nagesh
authors: Abburi
authors: A
authors: Krishnaiah
authors: Vishnu Mukund
authors: VM
authors: Dhople
authors: Curum S
authors: CS
authors: Sundaram
authors: Medicharla V
authors: MV
authors: Jagannadham
mesh_terms: D000166:Acridines / Q000737:chemistry*; D002412:Cations; D002621:Chemistry / Q000379:methods; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry; D007477:Ions; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013696:Temperature
chemical_list: D000166:Acridines; D002412:Cations; D004277:DNA, Single-Stranded; D007477:Ions; D009841:Oligonucleotides; D000644:Quaternary Ammonium Compounds; D004247:DNA