{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,22]],"date-time":"2026-01-22T03:56:57Z","timestamp":1769054217355,"version":"3.49.0"},"reference-count":40,"publisher":"Wiley","issue":"6","license":[{"start":{"date-parts":[[2006,8,10]],"date-time":"2006-08-10T00:00:00Z","timestamp":1155168000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecular Microbiology"],"published-print":{"date-parts":[[2006,9]]},"abstract":"<jats:title>Summary<\/jats:title><jats:p>The protozoan <jats:italic>Trypanosoma brucei<\/jats:italic> has a functional pteridine reductase (<jats:italic>Tb<\/jats:italic>PTR1), an NADPH\u2010dependent short\u2010chain reductase that participates in the salvage of pterins, which are essential for parasite growth. PTR1 displays broad\u2010spectrum activity with pterins and folates, provides a metabolic bypass for inhibition of the trypanosomatid dihydrofolate reductase and therefore compromises the use of antifolates for treatment of trypanosomiasis. Catalytic properties of recombinant <jats:italic>Tb<\/jats:italic>PTR1 and inhibition by the archetypal antifolate methotrexate have been characterized and the crystal structure of the ternary complex with cofactor NADP<jats:sup>+<\/jats:sup> and the inhibitor determined at 2.2\u2003\u00c5 resolution. This enzyme shares 50% amino acid sequence identity with <jats:italic>Leishmania major<\/jats:italic> PTR1 (<jats:italic>Lm<\/jats:italic>PTR1) and comparisons show that the architecture of the cofactor binding site, and the catalytic centre are highly conserved, as are most interactions with the inhibitor. However, specific amino acid differences, in particular the placement of Trp221 at the side of the active site, and adjustment of the \u03b26\u2010\u03b16 loop and \u03b16 helix at one side of the substrate\u2010binding cleft significantly reduce the size of the substrate binding site of <jats:italic>Tb<\/jats:italic>PTR1 and alter the chemical properties compared with <jats:italic>Lm<\/jats:italic>PTR1. A reactive Cys168, within the active site cleft, in conjunction with the C\u2010terminus carboxyl group and His267 of a partner subunit forms a triad similar to the catalytic component of cysteine proteases. <jats:italic>Tb<\/jats:italic>PTR1 therefore offers novel structural features to exploit in the search for inhibitors of therapeutic value against African trypanosomiasis.<\/jats:p>","DOI":"10.1111\/j.1365-2958.2006.05332.x","type":"journal-article","created":{"date-parts":[[2006,8,10]],"date-time":"2006-08-10T11:10:31Z","timestamp":1155208231000},"page":"1457-1468","source":"Crossref","is-referenced-by-count":58,"title":["Structure and reactivity of <i>Trypanosoma brucei<\/i> pteridine reductase: inhibition by the archetypal antifolate methotrexate"],"prefix":"10.1111","volume":"61","author":[{"given":"Alice","family":"Dawson","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Federica","family":"Gibellini","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Natasha","family":"Sienkiewicz","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lindsay B.","family":"Tulloch","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Paul K.","family":"Fyfe","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Karen","family":"McLuskey","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alan H.","family":"Fairlamb","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"William N.","family":"Hunter","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2006,8,10]]},"reference":[{"key":"e_1_2_5_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/0166-6851(90)90147-E"},{"key":"e_1_2_5_3_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.91.24.11442"},{"key":"e_1_2_5_4_1","doi-asserted-by":"publisher","DOI":"10.1002\/9780470123164.ch2"},{"key":"e_1_2_5_5_1","doi-asserted-by":"publisher","DOI":"10.1039\/p19850001349"},{"key":"e_1_2_5_6_1","doi-asserted-by":"publisher","DOI":"10.1107\/S0907444994003112"},{"key":"e_1_2_5_7_1","doi-asserted-by":"crossref","DOI":"10.1002\/0471220639","volume-title":"Enzymes, a Practical Introduction to Structure, Mechanism and Data Analysis","author":"Copeland R.A.","year":"2000"},{"key":"e_1_2_5_8_1","doi-asserted-by":"publisher","DOI":"10.1107\/S0907444998012645"},{"key":"e_1_2_5_9_1","volume-title":"The PyMOL Molecular Graphics System.","author":"DeLano W.L.","year":"2002"},{"key":"e_1_2_5_10_1","doi-asserted-by":"publisher","DOI":"10.1002\/prot.10512"},{"key":"e_1_2_5_11_1","doi-asserted-by":"publisher","DOI":"10.1107\/S0907444904019158"},{"key":"e_1_2_5_12_1","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.biophys.33.110502.140409"},{"key":"e_1_2_5_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.pt.2003.09.002"},{"key":"e_1_2_5_14_1","volume-title":"The Pharmaceutical Basis of Therapeutics. 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