{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T13:57:39Z","timestamp":1790863059598,"version":"4.1.0"},"reference-count":41,"publisher":"National Academy of Sciences","issue":"14","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2012,4,3]]},"abstract":"<jats:p>\n                    CRM197 is an enzymatically inactive and nontoxic form of diphtheria toxin that contains a single amino acid substitution (G52E). Being naturally nontoxic, CRM197 is an ideal carrier protein for conjugate vaccines against encapsulated bacteria and is currently used to vaccinate children globally against\n                    <jats:italic>Haemophilus influenzae<\/jats:italic>\n                    , pneumococcus, and meningococcus. To understand the molecular basis for lack of toxicity in CRM197, we determined the crystal structures of the full-length nucleotide-free CRM197 and of CRM197 in complex with the NAD hydrolysis product nicotinamide (NCA), both at 2.0-\u212b resolution. The structures show for the first time that the overall fold of CRM197 and DT are nearly identical and that the striking functional difference between the two proteins can be explained by a flexible active-site loop that covers the NAD binding pocket. We present the molecular basis for the increased flexibility of the active-site loop in CRM197 as unveiled by molecular dynamics simulations. These structural insights, combined with surface plasmon resonance, NAD hydrolysis, and differential scanning fluorimetry data, contribute to a comprehensive characterization of the vaccine carrier protein, CRM197.\n                  <\/jats:p>","DOI":"10.1073\/pnas.1201964109","type":"journal-article","created":{"date-parts":[[2012,3,20]],"date-time":"2012-03-20T00:57:11Z","timestamp":1332205031000},"page":"5229-5234","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":144,"title":["Structural basis for lack of toxicity of the diphtheria toxin mutant CRM197"],"prefix":"10.1073","volume":"109","author":[{"given":"Enrico","family":"Malito","sequence":"first","affiliation":[{"name":"Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121;"},{"name":"Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Badry","family":"Bursulaya","sequence":"additional","affiliation":[{"name":"Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Connie","family":"Chen","sequence":"additional","affiliation":[{"name":"Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121;"},{"name":"Joint Center for Structural Genomics, Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paola Lo","family":"Surdo","sequence":"additional","affiliation":[{"name":"Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Monica","family":"Picchianti","sequence":"additional","affiliation":[{"name":"Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy;"},{"name":"Department of Evolutionary Biology, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Enrico","family":"Balducci","sequence":"additional","affiliation":[{"name":"School of Biosciences and Biotechnologies, University of Camerino, via Gentile III da Varano, 62032 Camerino, Italy; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marco","family":"Biancucci","sequence":"additional","affiliation":[{"name":"Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy;"},{"name":"Department of Chemistry, University of Siena, Via A. De Gasperi 2, 53100 Siena, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ansgar","family":"Brock","sequence":"additional","affiliation":[{"name":"Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Francesco","family":"Berti","sequence":"additional","affiliation":[{"name":"Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew James","family":"Bottomley","sequence":"additional","affiliation":[{"name":"Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mikkel","family":"Nissum","sequence":"additional","affiliation":[{"name":"Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paolo","family":"Costantino","sequence":"additional","affiliation":[{"name":"Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rino","family":"Rappuoli","sequence":"additional","affiliation":[{"name":"Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Glen","family":"Spraggon","sequence":"additional","affiliation":[{"name":"Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121;"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2012,3,19]]},"reference":[{"key":"e_1_3_3_1_2","doi-asserted-by":"publisher","DOI":"10.1086\/315551"},{"key":"e_1_3_3_2_2","first-page":"177","article-title":"Diphtheria epidemic\u2014new independent states of the former Soviet Union, 1990\u20131994","volume":"44","year":"1995","unstructured":", Diphtheria epidemic\u2014new independent states of the former Soviet Union, 1990\u20131994. MMWR Morb Mortal Wkly Rep 44, 177\u2013181 (1995).","journal-title":"MMWR Morb Mortal Wkly Rep"},{"key":"e_1_3_3_3_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.182.4110.353"},{"key":"e_1_3_3_4_2","first-page":"629","article-title":"Contribution a l\u2019etude de la diphth\u00e9rie [Contribution to the study of diphtheria]","volume":"2","author":"Roux E","year":"1888","unstructured":"E Roux, A Yersin, Contribution a l\u2019etude de la diphth\u00e9rie [Contribution to the study of diphtheria]. Ann Inst Pasteur (Paris) 2, 629\u2013661, in French. (1888).","journal-title":"Ann Inst Pasteur (Paris)"},{"key":"e_1_3_3_5_2","first-page":"524","article-title":"Diphtheria toxoid as an immunizing agent","volume":"17","author":"FitzGerald JG","year":"1927","unstructured":"JG FitzGerald, Diphtheria toxoid as an immunizing agent. 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