Non‐covalent dimers of the lysine containing protonated peptide ions in gaseous state: electrospray ionization mass spectrometric study |
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Authors: | Shibdas Banerjee Shyamalava Mazumdar |
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Institution: | Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India |
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Abstract: | Study of the non‐covalent molecular complexes in gas phase by electrospray ionization mass spectrometry (ESI‐MS) represents a promising strategy to probe the intrinsic nature of these complexes. ESI‐MS investigation of a series of synthetic octapeptides containing six alanine and two lysine residues differing only by their positions showed the formation of non‐covalent dimers, which were preserved in the gas phase. Unlike the monomers, the dimers were found to show only singly protonated state. The decrease in the solvent polarity from water to alcohol showed enhanced propensity of formation of the dimer indicating that the electrostatic interaction plays a crucial role to stabilize the dimer. Selective functionalization studies showed that ε‐NH2 of lysine and C‐terminal amide (? CONH2) facilitate the dimerization through intermolecular hydrogen bonding network. Copyright © 2010 John Wiley & Sons, Ltd. |
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Keywords: | peptides non‐covalent dimer ESI‐MS ionic interaction hydrogen bonding |
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