title: Peptide structural analysis using continuous Ar cluster and C60 ion beams.
abstract: A novel application of time-of-flight secondary ion mass spectrometry (ToF-SIMS) with continuous Ar cluster beams to peptide analysis was investigated. In order to evaluate peptide structures, it is necessary to detect fragment ions related to multiple neighbouring amino acid residues. It is, however, difficult to detect these using conventional ToF-SIMS primary ion beams such as Bi cluster beams. Recently, C60 and Ar cluster ion beams have been introduced to ToF-SIMS as primary ion beams and are expected to generate larger secondary ions than conventional ones. In this study, two sets of model peptides have been studied: (des-Tyr)-Leu-enkephalin and (des-Tyr)-Met-enkephalin (molecular weights are approximately 400 Da), and [Asn(1) Val(5)]-angiotensin II and [Val(5)]-angiotensin I (molecular weights are approximately 1,000 Da) in order to evaluate the usefulness of the large cluster ion beams for peptide structural analysis. As a result, by using the Ar cluster beams, peptide molecular ions and large fragment ions, which are not easily detected using conventional ToF-SIMS primary ion beams such as Bi3 (+), are clearly detected. Since the large fragment ions indicating amino acid sequences of the peptides are detected by the large cluster beams, it is suggested that the Ar cluster and C60 ion beams are useful for peptide structural analysis.
authors.affiliation: Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu-cho, Matsue-shi, Shimane, 690-8504, Japan. aoyagi@life.shimane-u.ac.jp
authors.forename: Satoka
authors.initials: S
authors.lastname: Aoyagi
authors.forename: John S
authors.initials: JS
authors.lastname: Fletcher
authors.forename: Sadia
authors.initials: S
authors.lastname: Sheraz Rabbani
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kawashima
authors.forename: Irma
authors.initials: I
authors.lastname: Berrueta Razo
authors.forename: Alex
authors.initials: A
authors.lastname: Henderson
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Lockyer
authors.forename: John C
authors.initials: JC
authors.lastname: Vickerman
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis* / Q000737:chemistry* / Q000528:radiation effects; D001128:Argon / Q000737:chemistry*; D037741:Fullerenes / Q000737:chemistry*; D020450:Heavy Ions; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis* / Q000737:chemistry* / Q000528:radiation effects; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000596:Amino Acids; D037741:Fullerenes; D010455:Peptides; D001128:Argon; C069837:fullerene C60