Author
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Ralston, Nicholas |
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Hunt, Curtiss |
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Submitted to: Experimental Biology
Publication Type: Abstract Only Publication Acceptance Date: 4/17/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Boron forms reversible anionic mono- and dicomplexes with biomolecules by interacting with vicinal cis-diols on the ligand. We used an in vitro model system to investigate the binding of boron to various adenosine ribonucleotides including adenosine di- and tri-phosphate (ADP and ATP) and diadenosine tetraphosphate (A2P4), a signal nucleotide that regulates cell proliferation and stress response. Boron binding increases the relative migration time (sample migration time/neutral standard migration time; uT) of the ligand in CE because of the addition of the negative charge. On the other hand, umT of a ligand is reduced in CE when changes in molecular configuration result in a reduced hydrodynamic diameter (HD). Four independent samples of these ribonucleotides were chromatographed by CE at 25 kV through 50 cm x 50 umm silica capillaries using 200 mM Tricine at pH 8.4. As expected, the umT for each ligand was proportional to the HD/charge ratio of each molecule: A2P4, 3.38+/-0.06; ADP, 4.31+/-0.07; ATP, 5.10+/-0.06. Contrary to expectations, increasing concentrations of boron from 1-60 mM in the running buffer decreased ligand umT in all cases and increases in umT did not occur until boron concentrations >60 mM were tested. Increases in ligand umT observed in 60-200 mM boron are indicative of boromonoester formation, but decreased umT in 1-60 mM boron is a novel observation. Because cis-diol compounds form dicomplexes when ligand stoichiometry is in excess, the decreased umT may indicate reduced HD as a result of dicomplex spiro-cyclic formation. These findings are being examined further to determine their physiological significance. |
