{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,9]],"date-time":"2026-06-09T13:14:34Z","timestamp":1781010874419,"version":"3.54.1"},"reference-count":30,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2022,3,15]],"date-time":"2022-03-15T00:00:00Z","timestamp":1647302400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004837","name":"Spanish Ministry of Science and Innovation","doi-asserted-by":"publisher","award":["PID2020-113225GB-I00"],"award-info":[{"award-number":["PID2020-113225GB-I00"]}],"id":[{"id":"10.13039\/501100004837","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Salp15 is one of the proteins in the saliva of the tick Ixodes scapularis. Together with other biomolecules injected into the mammalian host at the biting site, it helps the tick to sustain its blood meal for days. Salp15 interferes with the cellular immune response of the mammalian host by inhibiting the activation of CD4+ T-lymphocytes. This function is co-opted by pathogens that use the tick as a vector and invade the host when the tick bites, such as Borrelia burgdorferi, the causative agent of Lyme borreliosis. Because of the immunity-suppressing role of Salp15, it has been proposed as a candidate for therapeutic applications in disorders of the immune system. The protein is produced as a 135-residue long polypeptide and secreted without its N-terminal signal 1\u201321 sequence. Detailed structural studies on Salp15 are lacking because of the difficulty in producing large amounts of the folded protein. We report the production of Salp15 and its structural analysis by NMR. The protein is monomeric and contains a flexible N-terminal region followed by a folded domain with mixed \u03b1 + \u03b2 secondary structures. Our results are consistent with a three-dimensional structural model derived from AlphaFold, which predicts the formation of three disulfide bridges and a free C-terminal cysteine.<\/jats:p>","DOI":"10.3390\/ijms23063134","type":"journal-article","created":{"date-parts":[[2022,3,16]],"date-time":"2022-03-16T03:34:13Z","timestamp":1647401653000},"page":"3134","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Structural Analysis of the Black-Legged Tick Saliva Protein Salp15"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2761-2336","authenticated-orcid":false,"given":"Bel\u00e9n","family":"Chaves-Arquero","sequence":"first","affiliation":[{"name":"Centro de Investigaciones Biol\u00f3gicas, CIB-CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cecilia","family":"Persson","sequence":"additional","affiliation":[{"name":"Swedish NMR Centre, Medicinaregatan 5c, 41390 Goteborg, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nekane","family":"Merino","sequence":"additional","affiliation":[{"name":"CIC bioGUNE, Parque Cient\u00edfico y Tecnol\u00f3gico de Bizkaia, 48160 Derio, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0812-0395","authenticated-orcid":false,"given":"Julen","family":"Tom\u00e1s-Cortazar","sequence":"additional","affiliation":[{"name":"CIC bioGUNE, Parque Cient\u00edfico y Tecnol\u00f3gico de Bizkaia, 48160 Derio, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7358-3505","authenticated-orcid":false,"given":"Adriana L.","family":"Rojas","sequence":"additional","affiliation":[{"name":"CIC bioGUNE, Parque Cient\u00edfico y Tecnol\u00f3gico de Bizkaia, 48160 Derio, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2061-7182","authenticated-orcid":false,"given":"Juan","family":"Anguita","sequence":"additional","affiliation":[{"name":"CIC bioGUNE, Parque Cient\u00edfico y Tecnol\u00f3gico de Bizkaia, 48160 Derio, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2545-4319","authenticated-orcid":false,"given":"Francisco J.","family":"Blanco","sequence":"additional","affiliation":[{"name":"Centro de Investigaciones Biol\u00f3gicas, CIB-CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,3,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Pham, M., Underwood, J., and Ch\u00e1vez, A.S.O. 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