Intrinsic amino acid size parameters from a series of 113 lysine-terminated tryptic digest peptide ions

Citation
Sj. Valentine et al., Intrinsic amino acid size parameters from a series of 113 lysine-terminated tryptic digest peptide ions, J PHYS CH B, 103(8), 1999, pp. 1203-1207
Citations number
43
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF PHYSICAL CHEMISTRY B
ISSN journal
15206106 → ACNP
Volume
103
Issue
8
Year of publication
1999
Pages
1203 - 1207
Database
ISI
SICI code
1520-6106(19990225)103:8<1203:IAASPF>2.0.ZU;2-C
Abstract
Cross sections for mixtures of tryptic digest peptide ions formed by electr ospray ionization have been measured by a new ion mobility/time-of-flight m ass spectrometry technique. Analysis of a series of 113 peptides containing 5-10 residues and having a single lysine group located at the C-terminal e nd show that cross sections are largely dependent upon the amino acid compo sition of each peptide. Reduced cross sections (which take into account dif ferences in mass) are found to correlate with the fractions of nonpolar or polar aliphatic residues. Average intrinsic contributions to size for indiv idual amino acid residues (referred to as intrinsic size parameters) have b een obtained by solving a system of equations that relates the 113 reduced cross sections to the occurrence frequency of each residue within the diffe rent sequences. These parameters fall into families according to the physic al sizes and chemical properties of the amino acids; contributions to cross section from nonpolar residues are significantly larger than those from po lar groups. Calculated cross sections that are obtained by combining intrin sic size factors with peptide sequences are remarkably accurate: >90% of ca lculated values are within 2% of experimental measurements.