{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,14]],"date-time":"2026-01-14T18:47:52Z","timestamp":1768416472219,"version":"3.49.0"},"reference-count":24,"publisher":"Wiley","issue":"7","license":[{"start":{"date-parts":[[2008,12,31]],"date-time":"2008-12-31T00:00:00Z","timestamp":1230681600000},"content-version":"vor","delay-in-days":4201,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Protein Science"],"published-print":{"date-parts":[[1997,7]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>The wide range of receptor binding affinities reported to result from mutations at residue Gly 33 of the cholera toxin B\u2010pentamer (CTB) has been most puzzling. For instance, introduction of an aspartate at this position abolishes receptor binding, whereas substitution by arginine retains receptor affinity despite the larger side chain.<\/jats:p><jats:p>We now report the structure determination and 2.3\u2010\u00c5 refinement of the CTB mutant Gly 33 \u2192 Arg complexed with the G<jats:sub>m1<\/jats:sub> oligosaccharide, as well as the 2.2\u2010\u00c5 refinement of a Gly 33 \u2192 Asp mutant of the closely related <jats:italic>Escherichia coli<\/jats:italic> heat\u2010labile enterotoxin B\u2010pentamer (LTB). Two of the five receptor binding sites in the Gly 33 \u2192 Arg CTB mutant are occupied by bound G<jats:sub>M1<\/jats:sub> oligosaccharide; two other sites are involved in a reciprocal toxin:toxin interaction; one site is unoccupied. We further report a higher resolution (2.0 \u00c5) determination and refinement of the wild\u2010type CTB:G<jats:sub>M1<\/jats:sub>oligosaccharide complex in which all five oligosaccharides are seen to be bound in essentially identical conformations. Saccharide conformation and binding interactions are very similar in both the CTB wild\u2010type and Gly 33 \u2192 Arg mutant complexes.<\/jats:p><jats:p>The protein conformation observed for the binding\u2010deficient Gly 33 \u2192 Asp mutant of LTB does not differ substantially from that seen in the toxin:saccharide complexes. The critical nature of the side chain of residue 33 is apparently due to a limited range of subtle rearrangements available to both the toxin and the saccharide to accommodate receptor binding. The intermolecular interactions seen in the CTB (Gly 33 \u2192 Arg) complex with oligosaccharide suggest that the affinity of this mutant for the receptor is close to the self\u2010affinity corresponding to the toxin:toxin binding interaction that has now been observed in crystal structures of three CTB mutants.<\/jats:p>","DOI":"10.1002\/pro.5560060716","type":"journal-article","created":{"date-parts":[[2009,2,10]],"date-time":"2009-02-10T05:55:35Z","timestamp":1234245335000},"page":"1516-1528","source":"Crossref","is-referenced-by-count":91,"title":["Structural studies of receptor binding by cholera toxin mutants"],"prefix":"10.1002","volume":"6","author":[{"given":"Ethan A.","family":"Merritt","sequence":"first","affiliation":[]},{"given":"Steve","family":"Sarfaty","sequence":"additional","affiliation":[]},{"given":"WIM G.J.","family":"Hol","sequence":"additional","affiliation":[]},{"given":"Michael G.","family":"Jobling","sequence":"additional","affiliation":[]},{"given":"Randall K.","family":"Holmes","sequence":"additional","affiliation":[]},{"given":"T.","family":"Chang","sequence":"additional","affiliation":[]},{"given":"Timothy R.","family":"Hirst","sequence":"additional","affiliation":[]}],"member":"311","published-online":{"date-parts":[[2008,12,31]]},"reference":[{"key":"e_1_2_1_2_1","doi-asserted-by":"publisher","DOI":"10.1021\/ja00177a043"},{"key":"e_1_2_1_3_1","doi-asserted-by":"publisher","DOI":"10.1006\/prep.1994.1031"},{"key":"e_1_2_1_4_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.91.25.11859"},{"key":"e_1_2_1_5_1","volume-title":"X\u2010PLOR (version 3.0) Manual","author":"Br\u00fcnger A.","year":"1990"},{"key":"e_1_2_1_6_1","doi-asserted-by":"publisher","DOI":"10.1107\/S0021889883010985"},{"key":"e_1_2_1_7_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2958.1995.tb02289.x"},{"key":"e_1_2_1_8_1","doi-asserted-by":"crossref","first-page":"1748","DOI":"10.1128\/iai.56.7.1748-1753.1988","article-title":"Comparison of the carbohydrate\u2010binding specificities of cholera toxin and Escherichia coli heat\u2010labile enterotoxins LTh\u2010I, LT\u2010IIa and LT\u2010IIb","volume":"56","author":"Fukuta S","year":"1988","journal-title":"Infect Immun"},{"key":"e_1_2_1_9_1","doi-asserted-by":"crossref","first-page":"851","DOI":"10.1128\/iai.8.6.851-859.1973","article-title":"Comparison of the tissue receptors for Vibrio cholerae and Escherichia coli enterotoxins by means of gangliosides and natural cholera toxoid","volume":"8","author":"Holmgren J.","year":"1913","journal-title":"Infect Immun"},{"key":"e_1_2_1_10_1","first-page":"163","volume-title":"Progress in brain research","author":"Holmgren J.","year":"1994"},{"key":"e_1_2_1_11_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2958.1991.tb01925.x"},{"key":"e_1_2_1_12_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jmii.2015.02.259"},{"key":"e_1_2_1_13_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-3083.1994.tb03505.x"},{"key":"e_1_2_1_14_1","volume-title":"Practical protein crystallography","author":"McRee D.","year":"1993"},{"key":"e_1_2_1_15_1","doi-asserted-by":"publisher","DOI":"10.1016\/0959-440X(95)80071-9"},{"key":"e_1_2_1_16_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0969-2126(01)00190-3"},{"key":"e_1_2_1_17_1","doi-asserted-by":"publisher","DOI":"10.1002\/pro.5560030202"},{"key":"e_1_2_1_18_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2958.1994.tb00467.x"},{"key":"e_1_2_1_19_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.93.1.226"},{"key":"e_1_2_1_20_1","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.270.50.29953"},{"key":"e_1_2_1_21_1","doi-asserted-by":"publisher","DOI":"10.1021\/bi00494a014"},{"key":"e_1_2_1_22_1","doi-asserted-by":"crossref","first-page":"13233","DOI":"10.1016\/S0021-9258(18)51619-7","article-title":"Binding of Vibrio cholerae toxin and the heat\u2010labile enterotoxin of Escherichia coli to GM1, derivatives of GM1, and nonlipid oligosaccharide polyvalent ligands","volume":"264","author":"Schengrund CL","year":"1989","journal-title":"J Biol Chem"},{"key":"e_1_2_1_23_1","doi-asserted-by":"publisher","DOI":"10.1021\/bi00438a017"},{"key":"e_1_2_1_24_1","doi-asserted-by":"publisher","DOI":"10.1006\/jmbi.1993.1209"},{"key":"e_1_2_1_25_1","doi-asserted-by":"crossref","first-page":"8552","DOI":"10.1016\/S0021-9258(17)39508-X","article-title":"Analysis of receptor\u2010binding site in Escherichia coli enterotoxin","volume":"260","author":"Tsuji T","year":"1985","journal-title":"J Biol Chem"}],"container-title":["Protein Science"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Fpro.5560060716","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/pro.5560060716","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,10,28]],"date-time":"2023-10-28T01:31:06Z","timestamp":1698456666000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/pro.5560060716"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1997,7]]},"references-count":24,"journal-issue":{"issue":"7","published-print":{"date-parts":[[1997,7]]}},"alternative-id":["10.1002\/pro.5560060716"],"URL":"https:\/\/doi.org\/10.1002\/pro.5560060716","archive":["Portico"],"relation":{},"ISSN":["0961-8368","1469-896X"],"issn-type":[{"value":"0961-8368","type":"print"},{"value":"1469-896X","type":"electronic"}],"subject":[],"published":{"date-parts":[[1997,7]]}}}