title: Effect of charge on the conformation of highly basic peptides including the tail regions of histone proteins by ion mobility mass spectrometry.
abstract: The first systematic and comprehensive study of the charging behaviour and effect of charge on the conformation of specifically constructed arginine-rich peptides and its significance to the N- and C-terminal basic tail regions of histone proteins was conducted using ion mobility mass spectrometry (IM-MS). Among the basic amino acids, arginine has the greatest impact on the charging behaviour and structures of gas phase ions by virtue of its high proton affinity. A close linear correlation was found between either the maximum charge, or most abundant charge state, that the peptides support and their average collision cross section (CCS) values measured by ion mobility mass spectrometry. The calculated collision cross sections for the lowest energy solution state models predicted by the PEP-FOLD algorithm using a modified MOBCAL trajectory method were found to best correlate with the values measured by IM-MS. In the case of the histone peptides, more compact folded structures, supporting less than the maximum number of charges, were observed. These results are consistent with those previously reported for histone dimers where neutralization of the charge at the basic residues of the tail regions did not affect their CCS values.
authors.affiliation: Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Akashi
authors.affiliation: Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan. kevin.downard@unsw.edu.au.|Faculty of Medicine, University of New South Wales, Sydney, New South Wales, 2052, Australia. kevin.downard@unsw.edu.au.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Downard
mesh_terms: D000595:Amino Acid Sequence; D001120:Arginine / Q000737:chemistry; D006657:Histones / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008239:Lysine / Q000737:chemistry; D008958:Models, Molecular; D009842:Oligopeptides / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D055672:Static Electricity
chemical_list: D006657:Histones; D007477:Ions; D009842:Oligopeptides; D010455:Peptides; D001120:Arginine; D008239:Lysine
keywords: Charge; Conformation; Ion mobility; Mass spectrometry; Peptide; Structure