{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T17:59:56Z","timestamp":1775066396202,"version":"3.50.1"},"reference-count":48,"publisher":"Proceedings of the National Academy of Sciences","issue":"39","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2004,9,28]]},"abstract":"<jats:p>Electron capture dissociation (ECD) MS is proving to be unusually valuable for \u201ctop down\u201d protein sequencing and identification\/localization of posttranslational modifications, because the ECD product ions can represent cleavages between most of a protein's amino acids. As proposed, this unusual reactivity results from immediate local utilization, before randomization, of much of the relatively large (\u22486 eV) energy from the electron reaction with the multiply charged protein ion, minimizing the effect of differences in the backbone bond dissociation energies. However, others conclude that e<jats:sup>\u2013<\/jats:sup>capture produces a labile free radical species for which backbone cleavage is the lowest energy reaction. Supporting the nonergodic mechanism, ECD of ubiquitin (M + 12H)<jats:sup>12+<\/jats:sup>ions also yields thermalized radical (M + 12H)<jats:sup>11+\u00b7<\/jats:sup>ions that instead lose H\u00b7 when activated. Also, the ECD spectrum of ubiquitin (M + 13H)<jats:sup>13+<\/jats:sup>ions is nearly unchanged by heating from 25\u00b0C to 125\u00b0C, demonstrating that this increase in thermal energy is small compared to the energy driving the reaction. These results support initial capture of the electron in a long-lived high-<jats:italic>n<\/jats:italic>Rydberg state, followed by internal conversion to the product valence state at an energy well above the dissociation barriers. The instantaneous conformation of the valence state is critical, with the observed products supporting an \u03b1-helical structure in which the protonated side chain of each basic residue is intercalated to hydrogen-bond to as many as three amide carbonyls. Activation (e.g., heat, collisions, lowered charge) can disrupt this conformation to allow additional H<jats:sup>+<\/jats:sup>-side-chain interactions and provide more complete sequence coverage.<\/jats:p>","DOI":"10.1073\/pnas.0406095101","type":"journal-article","created":{"date-parts":[[2004,9,21]],"date-time":"2004-09-21T00:25:03Z","timestamp":1095726303000},"page":"14011-14016","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":153,"title":["Nonergodic and conformational control of the electron capture dissociation of protein cations"],"prefix":"10.1073","volume":"101","author":[{"given":"Kathrin","family":"Breuker","sequence":"first","affiliation":[{"name":"Institute of Organic Chemistry, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria; Department of Chemistry, Sogang University, Seoul 121-742, South Korea; and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853-1301"}]},{"given":"HanBin","family":"Oh","sequence":"additional","affiliation":[{"name":"Institute of Organic Chemistry, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria; Department of Chemistry, Sogang University, Seoul 121-742, South Korea; and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853-1301"}]},{"given":"Cheng","family":"Lin","sequence":"additional","affiliation":[{"name":"Institute of Organic Chemistry, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria; Department of Chemistry, Sogang University, Seoul 121-742, South Korea; and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853-1301"}]},{"given":"Barry K.","family":"Carpenter","sequence":"additional","affiliation":[{"name":"Institute of Organic Chemistry, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria; Department of Chemistry, Sogang University, Seoul 121-742, South Korea; and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853-1301"}]},{"given":"Fred W.","family":"McLafferty","sequence":"additional","affiliation":[{"name":"Institute of Organic Chemistry, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria; Department of Chemistry, Sogang University, Seoul 121-742, South Korea; and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853-1301"}]}],"member":"341","published-online":{"date-parts":[[2004,9,20]]},"reference":[{"key":"e_1_3_2_1_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja973478k"},{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja981948k"},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1387-3806(98)14215-X"},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.1021\/ac990811p"},{"key":"e_1_3_2_5_2","doi-asserted-by":"publisher","DOI":"10.1021\/ac990578v"},{"key":"e_1_3_2_6_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0402700101"},{"key":"e_1_3_2_7_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.251691898"},{"key":"e_1_3_2_8_2","doi-asserted-by":"publisher","DOI":"10.1021\/ac020446t"},{"key":"e_1_3_2_9_2","doi-asserted-by":"publisher","DOI":"10.1021\/ar50137a002"},{"key":"e_1_3_2_10_2","doi-asserted-by":"publisher","DOI":"10.1016\/0009-2614(89)85180-2"},{"key":"e_1_3_2_11_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.279.5352.847"},{"key":"e_1_3_2_12_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja026230q"},{"key":"e_1_3_2_13_2","doi-asserted-by":"publisher","DOI":"10.1002\/poc.672"},{"key":"e_1_3_2_14_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00321a006"},{"key":"e_1_3_2_15_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00075a054"},{"key":"e_1_3_2_16_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja021162t"},{"key":"e_1_3_2_17_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja021323t"},{"key":"e_1_3_2_18_2","doi-asserted-by":"publisher","DOI":"10.1002\/jms.527"},{"key":"e_1_3_2_19_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp021402r"},{"key":"e_1_3_2_20_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja028831n"},{"key":"e_1_3_2_21_2","doi-asserted-by":"publisher","DOI":"10.5702\/massspec.50.229"},{"key":"e_1_3_2_22_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp035675d"},{"key":"e_1_3_2_23_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijms.2004.01.020"},{"key":"e_1_3_2_24_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja973655h"},{"key":"e_1_3_2_25_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.2675315"},{"key":"e_1_3_2_26_2","doi-asserted-by":"publisher","DOI":"10.1021\/ac00090a003"},{"key":"e_1_3_2_27_2","doi-asserted-by":"publisher","DOI":"10.1021\/ac00090a004"},{"key":"e_1_3_2_28_2","doi-asserted-by":"publisher","DOI":"10.1103\/PhysRevA.18.64"},{"key":"e_1_3_2_29_2","doi-asserted-by":"publisher","DOI":"10.1021\/ar9702987"},{"key":"e_1_3_2_30_2","doi-asserted-by":"crossref","first-page":"2369","DOI":"10.1021\/jp003466c","volume":"105","year":"2001","unstructured":"Datz, S. (2001) J. Phys. Chem. A 105, 2369\u20132373.","journal-title":"J. Phys. Chem. A"},{"key":"e_1_3_2_31_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1044-0305(99)00157-9"},{"key":"e_1_3_2_32_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1387-3806(02)00529-8"},{"key":"e_1_3_2_33_2","doi-asserted-by":"publisher","DOI":"10.1255\/ejms.487"},{"key":"e_1_3_2_34_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1044-0305(01)00209-4"},{"key":"e_1_3_2_35_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja012267j"},{"key":"e_1_3_2_36_2","first-page":"37","volume":"185","year":"1999","unstructured":"Li, J., Taraszka, J. A., Counterman, A. E. & Clemmer, D. E. (1999) Int. J. Mass Spectrom. 185\/186\/187, 37\u201347.","journal-title":"Int. J. Mass Spectrom."},{"key":"e_1_3_2_37_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.212643599"},{"key":"e_1_3_2_38_2","doi-asserted-by":"publisher","DOI":"10.1021\/ac960804q"},{"key":"e_1_3_2_39_2","doi-asserted-by":"publisher","DOI":"10.1021\/ar00033a001"},{"key":"e_1_3_2_40_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja048766c"},{"key":"e_1_3_2_41_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja9728076"},{"key":"e_1_3_2_42_2","first-page":"565","volume":"185","year":"1999","unstructured":"Freitas, M. A., Hendrickson, C. L., Emmett, M. R. & Marshall, A. G. (1999) Int. J. Mass Spectrom. 185\/186\/187, 565\u2013575.","journal-title":"Int. J. Mass Spectrom."},{"key":"e_1_3_2_43_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00130a015"},{"key":"e_1_3_2_44_2","doi-asserted-by":"publisher","DOI":"10.1063\/1.464913"},{"key":"e_1_3_2_45_2","doi-asserted-by":"publisher","DOI":"10.1103\/PhysRevB.37.785"},{"key":"e_1_3_2_46_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.1091708"},{"key":"e_1_3_2_47_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.267.5203.1483"},{"key":"e_1_3_2_48_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1044-0305(02)00374-4"}],"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.0406095101","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,4,29]],"date-time":"2023-04-29T10:14:10Z","timestamp":1682763250000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.0406095101"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2004,9,20]]},"references-count":48,"journal-issue":{"issue":"39","published-print":{"date-parts":[[2004,9,28]]}},"alternative-id":["10.1073\/pnas.0406095101"],"URL":"https:\/\/doi.org\/10.1073\/pnas.0406095101","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[2004,9,20]]},"assertion":[{"value":"2004-09-20","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}