{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,10]],"date-time":"2026-04-10T20:16:34Z","timestamp":1775852194153,"version":"3.50.1"},"reference-count":69,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2022,1,10]],"date-time":"2022-01-10T00:00:00Z","timestamp":1641772800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003593","name":"National Council for Scientific and Technological Development","doi-asserted-by":"publisher","award":["206385\/2014-5"],"award-info":[{"award-number":["206385\/2014-5"]}],"id":[{"id":"10.13039\/501100003593","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Government of Libya","award":["Scholarship"],"award-info":[{"award-number":["Scholarship"]}]},{"DOI":"10.13039\/501100000780","name":"European Union","doi-asserted-by":"publisher","award":["Erasmus+"],"award-info":[{"award-number":["Erasmus+"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]},{"name":"International Association for the Exchange of Students for Technical Experience","award":["Bursary"],"award-info":[{"award-number":["Bursary"]}]},{"name":"Ministry of Health, Saudi Arabia","award":["Fellowship"],"award-info":[{"award-number":["Fellowship"]}]},{"DOI":"10.13039\/501100003130","name":"Research Foundation - Flanders","doi-asserted-by":"publisher","award":["1226921 N"],"award-info":[{"award-number":["1226921 N"]}],"id":[{"id":"10.13039\/501100003130","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000265","name":"Medical Research Council","doi-asserted-by":"publisher","award":["MR\/S024573\/1"],"award-info":[{"award-number":["MR\/S024573\/1"]}],"id":[{"id":"10.13039\/501100000265","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Toxoplasma gondii is unable to synthesize purines de novo, instead salvages them from its environment, inside the host cell, for which they need high affinity carriers. Here, we report the expression of a T. gondii Equilibrative Nucleoside Transporter, Tg244440, in a Trypanosoma brucei strain from which nucleobase transporters have been deleted. Tg244440 transported hypoxanthine and guanine with similar affinity (Km ~1 \u00b5M), while inosine and guanosine displayed Ki values of 4.05 and 3.30 \u00b5M, respectively. Low affinity was observed for adenosine, adenine, and pyrimidines, classifying Tg244440 as a high affinity oxopurine transporter. Purine analogues were used to probe the substrate-transporter binding interactions, culminating in quantitative models showing different binding modes for oxopurine bases, oxopurine nucleosides, and adenosine. Hypoxanthine and guanine interacted through protonated N1 and N9, and through unprotonated N3 and N7 of the purine ring, whereas inosine and guanosine mostly employed the ribose hydroxy groups for binding, in addition to N1H of the nucleobase. Conversely, the ribose moiety of adenosine barely made any contribution to binding. Tg244440 is the first gene identified to encode a high affinity oxopurine transporter in T. gondii and, to the best of our knowledge, the first purine transporter to employ different binding modes for nucleosides and nucleobases.<\/jats:p>","DOI":"10.3390\/ijms23020710","type":"journal-article","created":{"date-parts":[[2022,1,10]],"date-time":"2022-01-10T17:42:25Z","timestamp":1641836545000},"page":"710","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["A Toxoplasma gondii Oxopurine Transporter Binds Nucleobases and Nucleosides Using Different Binding Modes"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6542-0485","authenticated-orcid":false,"given":"Gustavo D.","family":"Campagnaro","sequence":"first","affiliation":[{"name":"Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9339-6002","authenticated-orcid":false,"given":"Hamza A. A.","family":"Elati","sequence":"additional","affiliation":[{"name":"Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sofia","family":"Balaska","sequence":"additional","affiliation":[{"name":"Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Maria Esther","family":"Martin Abril","sequence":"additional","affiliation":[{"name":"Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manal J.","family":"Natto","sequence":"additional","affiliation":[{"name":"Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7470-3484","authenticated-orcid":false,"given":"Fabian","family":"Hulpia","sequence":"additional","affiliation":[{"name":"Laboratory for Medicinal Chemistry, Campus Heymans, Ghent University, Ottergemsesteenweg 460, B-9000 Gent, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kelly","family":"Lee","sequence":"additional","affiliation":[{"name":"Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5909-2307","authenticated-orcid":false,"given":"Lilach","family":"Sheiner","sequence":"additional","affiliation":[{"name":"Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK"},{"name":"Wellcome Centre for Integrative Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4201-1264","authenticated-orcid":false,"given":"Serge","family":"Van Calenbergh","sequence":"additional","affiliation":[{"name":"Laboratory for Medicinal Chemistry, Campus Heymans, Ghent University, Ottergemsesteenweg 460, B-9000 Gent, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9963-1827","authenticated-orcid":false,"given":"Harry P.","family":"de Koning","sequence":"additional","affiliation":[{"name":"Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1965","DOI":"10.1016\/S0140-6736(04)16412-X","article-title":"Toxoplasmosis","volume":"363","author":"Montoya","year":"2004","journal-title":"Lancet"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"264","DOI":"10.1128\/CMR.05013-11","article-title":"Epidemiology of and diagnostic strategies for toxoplasmosis","volume":"25","year":"2012","journal-title":"Clin. 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