کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1193979 | 1492364 | 2008 | 12 صفحه PDF | دانلود رایگان |
The sodium ion affinities of the amino acids Asn, Gln, His and Arg have been determined by experimental and computational approaches (for Asn, His and Arg). Na+-bound heterodimers with amino acid and peptide ligands (Pep1, Pep2) were produced by electrospray ionization. From the dissociation kinetics of these Pep1–Na+–Pep2 ions to Pep1–Na+ and Pep2–Na+, determined by collisionally activated dissociation, a ladder of relative affinities was constructed and subsequently converted to absolute affinities by anchoring the relative values to known Na+ affinities. The Na+ affinities of Asn, His and Arg, were calculated at the MP2(full)/6-311+G(2d,2p)//MP2/6-31G(d) level of ab initio theory. The resulting experimental and computed Na+ affinities are in excellent agreement with one another. These results, combined with those of our previous studies, yield the sodium ion affinities of 18 out of the 20 α-amino acids naturally occurring in peptides and proteins of living systems.
Journal: International Journal of Mass Spectrometry - Volume 269, Issues 1–2, 1 January 2008, Pages 34–45