{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T06:17:51Z","timestamp":1788416271198,"version":"build-2803163510"},"reference-count":42,"publisher":"American Chemical Society (ACS)","issue":"5","license":[{"start":{"date-parts":[[2019,5,23]],"date-time":"2019-05-23T00:00:00Z","timestamp":1558569600000},"content-version":"vor","delay-in-days":35,"URL":"https:\/\/pubs.acs.org\/page\/policy\/authorchoice_ccby_termsofuse.html"}],"funder":[{"DOI":"10.13039\/100010663","name":"H2020 European Research Council","doi-asserted-by":"publisher","award":["772027"],"award-info":[{"award-number":["772027"]}],"id":[{"id":"10.13039\/100010663","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001659","name":"Deutsche Forschungsgemeinschaft","doi-asserted-by":"publisher","award":["SFB 969"],"award-info":[{"award-number":["SFB 969"]}],"id":[{"id":"10.13039\/501100001659","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2019,5,17]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Electron paramagnetic resonance spectroscopy in combination with site-directed spin labeling (SDSL) is an important tool to obtain long-range distance restraints for protein structural research. We here study a variety of azide- and alkyne-bearing noncanonical amino acids (ncAA) in terms of protein single- and double-incorporation efficiency via nonsense suppression, metabolic stability, yields of nitroxide labeling via copper-catalyzed [3 + 2] azide\u2013alkyne cycloadditions (CuAAC), and spectroscopic properties in continuous-wave and double electron\u2013electron resonance measurements. We identify para-ethynyl-l-phenylalanine and para-propargyloxy-l-phenylalanine as suitable ncAA for CuAAC-based SDSL that will complement current SDSL approaches, particularly in cases in which essential cysteines of a target protein prevent the use of sulfhydryl-reactive spin labels.<\/jats:p>","DOI":"10.1021\/acschembio.8b01111","type":"journal-article","created":{"date-parts":[[2019,4,18]],"date-time":"2019-04-18T13:44:15Z","timestamp":1555595055000},"page":"839-844","source":"Crossref","is-referenced-by-count":40,"title":["Double Nitroxide Labeling by Copper-Catalyzed Azide\u2013Alkyne\nCycloadditions with Noncanonical Amino Acids for Electron Paramagnetic\nResonance Spectroscopy"],"prefix":"10.1021","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5068-2658","authenticated-orcid":true,"given":"Pia","family":"Widder","sequence":"first","affiliation":[{"name":"University of Konstanz , , ,","place":["Konstanz, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Frederic","family":"Berner","sequence":"additional","affiliation":[{"name":"University of Konstanz , , ,","place":["Konstanz, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3019-7241","authenticated-orcid":true,"given":"Daniel","family":"Summerer","sequence":"additional","affiliation":[{"name":"TU Dortmund University , , ,","place":["Dortmund, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3571-3452","authenticated-orcid":true,"given":"Malte","family":"Drescher","sequence":"additional","affiliation":[{"name":"University of Konstanz , , ,","place":["Konstanz, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2019,4,18]]},"reference":[{"key":"2026090302074126200_cit1","doi-asserted-by":"publisher","first-page":"9","DOI":"10.1042\/ETLS20170143","article-title":"The contribution\nof modern EPR to structural biology","volume":"2","author":"Jeschke","year":"2018","journal-title":"Emerging\nTop. 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Biol."},{"key":"2026090302074126200_cit37","doi-asserted-by":"publisher","first-page":"153","DOI":"10.1002\/9780470559277.ch110148","article-title":"Copper-Catalyzed Azide\u2013Alkyne\nClick Chemistry for Bioconjugation","volume":"3","author":"Presolski","year":"2011","journal-title":"Curr. Protoc.\nChem. Biol."},{"key":"2026090302074126200_cit38","doi-asserted-by":"publisher","first-page":"42","DOI":"10.1016\/j.jmr.2005.08.013","article-title":"Easy Spin, a comprehensive software package for spectral\nsimulation and analysis in EPR","volume":"178","author":"Stoll","year":"2006","journal-title":"J. Magn. 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