title: A database of alkaline-earth-coordinated peptide cross sections: insight into general aspects of structure.
abstract: A database of 1470 collision cross sections (666 doubly- and 804 triply-charged) of alkaline-earth-coordinated tryptic peptide ions [where the cation (M(2+)) correspond to Mg(2+), Ca(2+), or Ba(2+)] is presented. The utility of such an extensive set of measurements is illustrated by extraction of general properties of M(2+)-coordinated peptide structures. Specifically, we derive sets of intrinsic size parameters (ISPs) for individual amino acid residues for M(2+)-coordinated peptides. Comparison of these parameters with existing ISPs for protonated peptides suggests that M(2+) binding occurs primarily through interactions with specific polar aliphatic residues (Asp, Ser, and Thr) and the peptide backbone. A comparison of binding interactions for these alkaline-earth metals with interactions reported previously for alkali metals is provided. Finally, we describe a new analysis in which ISPs are used as probes for assessing peptide structure based on amino acid composition.
authors.affiliation: Department of Chemistry, Indiana University, Bloomington, IN 47405, USA.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Dilger
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Valentine
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Glover
authors.forename: David E
authors.initials: DE
authors.lastname: Clemmer
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D002118:Calcium / Q000737:chemistry; D002412:Cations / Q000737:chemistry; D056831:Coordination Complexes / Q000737:chemistry*; D016208:Databases, Factual; D006859:Hydrogen / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods; D008673:Metals, Alkaline Earth / Q000737:chemistry*; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D002412:Cations; D056831:Coordination Complexes; D008673:Metals, Alkaline Earth; D010455:Peptides; D006859:Hydrogen; D002118:Calcium