{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,9]],"date-time":"2026-10-09T19:56:13Z","timestamp":1791575773087,"version":"4.3.4"},"reference-count":0,"publisher":"National Academy of Sciences","issue":"12","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[1993,6,15]]},"abstract":"<jats:p>Giardia lamblia undergoes surface antigenic variation. The variant-specific\nsurface proteins (VSPs) are a distinct family of cysteine-rich proteins. Characteristically, cysteine\nresidues occur mostly as CXXC tetrapeptides. Four of the reported five VSPs contain a putative metal-binding\ndomain that resembles other metal-binding motifs; the fifth is closely related but lacks an essential\nhistidine. Three different native VSPs bound Zn2+. Co2+, Cu2+, and Cd2+ inhibited Zn2+ binding. Analysis\nof recombinant VSP fusion proteins showed that the putative binding motif bound Zn2+. Surprisingly, peptide\nfragments from other regions of the VSP contain numerous CXXCXnCXXC motifs that also bound Zn2+. Analysis\nof deduced amino acid sequences showed well-conserved CXXC spacing in three out of five VSPs, suggesting\nconservation of structure despite amino acid sequence divergence. The function of VSPs is unknown, but\nby binding Zn2+ or other metals in the intestine, VSPs may contribute to Zn2+ malnutrition or inhibition\nof metal-dependent intestinal enzymes, which would lead to malabsorption, a well-known consequence of\ngiardiasis.<\/jats:p>","DOI":"10.1073\/pnas.90.12.5489","type":"journal-article","created":{"date-parts":[[2006,5,31]],"date-time":"2006-05-31T08:25:13Z","timestamp":1149063913000},"page":"5489-5493","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":41,"title":["Variant-specific surface proteins of Giardia lamblia are zinc-binding proteins."],"prefix":"10.1073","volume":"90","author":[{"given":"T E","family":"Nash","sequence":"first","affiliation":[{"name":"Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious\rDiseases, National Institutes of Health, Bethesda, MD 20892."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M R","family":"Mowatt","sequence":"additional","affiliation":[{"name":"Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious\rDiseases, National Institutes of Health, Bethesda, MD 20892."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[1993,6,15]]},"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.90.12.5489","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,13]],"date-time":"2022-04-13T13:45:01Z","timestamp":1649857501000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.90.12.5489"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1993,6,15]]},"references-count":0,"journal-issue":{"issue":"12","published-print":{"date-parts":[[1993,6,15]]}},"alternative-id":["10.1073\/pnas.90.12.5489"],"URL":"https:\/\/doi.org\/10.1073\/pnas.90.12.5489","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[1993,6,15]]},"assertion":[{"value":"1993-06-15","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}