title: Highly Selective Dissociation of a Peptide Bond Following Excitation of Core Electrons.
abstract: The controlled breaking of a specific chemical bond with photons in complex molecules remains a major challenge in chemistry. In principle, using the K-edge absorption of a particular atomic element, one might excite selectively a specific atomic entity in a molecule. We report here highly selective dissociation of the peptide bonds in N-methylformamide and N-methylacetamide on tuning the X-ray wavelength to the K-edge absorption of the atoms connected to (or near) the peptide bond. The high selectivity (56-71%) of this cleavage arises from the large energy shift of X-ray absorption, a large overlap of the 1s orbital and the valence π* orbital that is highly localized on a peptide bond with antibonding character, and the relatively low bond energy of the peptide bonds. These characteristics indicate that the high selectivity on bond dissociation following core excitation could be a general feature for molecules containing peptide bonds.
authors.affiliation: †Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.|‡Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan.
authors.forename: Yi-Shiue
authors.initials: YS
authors.lastname: Lin
authors.affiliation: ⊥Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi 62102, Taiwan.
authors.forename: Cheng-Cheng
authors.initials: CC
authors.lastname: Tsai
authors.affiliation: †Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.|‡Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan.|§Department of Applied Chemistry, National Chiao Tung University, Hsinchu 30010, Taiwan.
authors.forename: Huei-Ru
authors.initials: HR
authors.lastname: Lin
authors.affiliation: †Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.|‡Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan.
authors.forename: Tsung-Lin
authors.initials: TL
authors.lastname: Hsieh
authors.affiliation: ‡Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan.|⊥Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi 62102, Taiwan.
authors.forename: Jien-Lian
authors.initials: JL
authors.lastname: Chen
authors.affiliation: ⊥Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi 62102, Taiwan.
authors.forename: Wei-Ping
authors.initials: WP
authors.lastname: Hu
authors.affiliation: ‡Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan.|∥Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Chi-Kung
authors.initials: CK
authors.lastname: Ni
authors.affiliation: †Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: Chen-Lin
authors.initials: CL
authors.lastname: Liu
mesh_terms: D000081:Acetamides / Q000737:chemistry*; D004583:Electrons; D005559:Formamides / Q000737:chemistry*; D013058:Mass Spectrometry; D010455:Peptides / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy / Q000379:methods
chemical_list: D000081:Acetamides; D005559:Formamides; D010455:Peptides; C018595:N-methylacetamide; C002950:methylformamide