{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T00:37:28Z","timestamp":1785458248046,"version":"3.56.0"},"reference-count":40,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2022,8,30]],"date-time":"2022-08-30T00:00:00Z","timestamp":1661817600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"NIH R21","award":["AI126583"],"award-info":[{"award-number":["AI126583"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>Parvovirus B19 (B19V) is a human pathogen that is the causative agent of fifth disease in children. It is also known to cause hydrops in fetuses, anemia in AIDS patients, and transient aplastic crisis in patients with sickle cell disease. The unique N-terminus of Viral Protein 1 (VP1u) of parvoviruses, including B19V, exhibits phospholipase A2 (PLA2) activity, which is required for endosomal escape. Presented is the structural dynamics of B19V VP1u under conditions that mimic the pHs of cell entry and endosomal trafficking to the nucleus. Using circular dichroism spectroscopy, the receptor-binding domain of B19V VP1u is shown to exhibit an \u03b1-helical fold, whereas the PLA2 domain exhibits a probable molten globule state, both of which are pH invariant. Differential scanning calorimetry performed at endosomal pHs shows that the melting temperature (Tm) of VP1u PLA2 domain is tuned to body temperature (37 \u00b0C) at pH 7.4. In addition, PLA2 assays performed at temperatures ranging from 25\u201345 \u00b0C show both a temperature and pH-dependent change in activity. We hypothesize that VP1u PLA2 domain differences in Tm at differing pHs have enabled the virus to \u201cswitch on\/off\u201d the phospholipase activity during capsid trafficking. Furthermore, we propose the environment of the early endosome as the optimal condition for endosomal escape leading to B19V infection.<\/jats:p>","DOI":"10.3390\/v14091922","type":"journal-article","created":{"date-parts":[[2022,8,31]],"date-time":"2022-08-31T02:09:36Z","timestamp":1661911776000},"page":"1922","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Structural Dynamics and Activity of B19V VP1u during the pHs of Cell Entry and Endosomal Trafficking"],"prefix":"10.3390","volume":"14","author":[{"given":"Renuk V.","family":"Lakshmanan","sequence":"first","affiliation":[{"name":"Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joshua A.","family":"Hull","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luke","family":"Berry","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew","family":"Burg","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1295-9609","authenticated-orcid":false,"given":"Brian","family":"Bothner","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2792-935X","authenticated-orcid":false,"given":"Robert","family":"McKenna","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mavis","family":"Agbandje-McKenna","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2133","DOI":"10.1007\/s00705-020-04632-4","article-title":"Reorganizing the family Parvoviridae: A revised taxonomy independent of the canonical approach based on host association","volume":"165","author":"Canuti","year":"2020","journal-title":"Arch. 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