{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,8]],"date-time":"2026-02-08T03:18:52Z","timestamp":1770520732890,"version":"3.49.0"},"reference-count":21,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2021,11,6]],"date-time":"2021-11-06T00:00:00Z","timestamp":1636156800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004462","name":"National Research Council","doi-asserted-by":"publisher","award":["CUP B86C17000270001"],"award-info":[{"award-number":["CUP B86C17000270001"]}],"id":[{"id":"10.13039\/501100004462","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004462","name":"National Research Council","doi-asserted-by":"publisher","award":["CUP B85F20002990005"],"award-info":[{"award-number":["CUP B85F20002990005"]}],"id":[{"id":"10.13039\/501100004462","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004271","name":"Sapienza University of Rome","doi-asserted-by":"publisher","award":["RM120172A76E4B78"],"award-info":[{"award-number":["RM120172A76E4B78"]}],"id":[{"id":"10.13039\/501100004271","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004588","name":"Istituto Pasteur","doi-asserted-by":"publisher","award":["Anna Tramontano grant"],"award-info":[{"award-number":["Anna Tramontano grant"]}],"id":[{"id":"10.13039\/501100004588","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Several variants of the enzyme pyridox(am)ine 5\u2032-phosphate oxidase (PNPO), responsible for a rare form of vitamin B6-dependent neonatal epileptic encephalopathy known as PNPO deficiency (PNPOD), have been reported. However, only a few of them have been characterised with respect to their structural and functional properties, despite the fact that the knowledge of how variants affect the enzyme may clarify the disease mechanism and improve treatment. Here, we report the characterisation of the catalytic, allosteric and structural properties of recombinantly expressed D33V, R161C, P213S, and E50K variants, among which D33V (present in approximately 10% of affected patients) is one of the more common variants responsible for PNPOD. The D33V and E50K variants have only mildly altered catalytic properties. In particular, the E50K variant, given that it has been found on the same chromosome with other known pathogenic variants, may be considered non-pathogenic. The P213S variant has lower thermal stability and reduced capability to bind the FMN cofactor. The variant involving Arg161 (R161C) largely decreases the affinity for the pyridoxine 5\u2032-phosphate substrate and completely abolishes the allosteric feedback inhibition exerted by the pyridoxal 5\u2032-phosphate product.<\/jats:p>","DOI":"10.3390\/ijms222112013","type":"journal-article","created":{"date-parts":[[2021,11,7]],"date-time":"2021-11-07T20:41:14Z","timestamp":1636317674000},"page":"12013","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Characterization of Novel Pathogenic Variants Causing Pyridox(am)ine 5\u2032-Phosphate Oxidase-Dependent Epilepsy"],"prefix":"10.3390","volume":"22","author":[{"given":"Anna","family":"Barile","sequence":"first","affiliation":[{"name":"Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, 00185 Rome, Italy"},{"name":"Dipartimento di Scienze Biochimiche \u201cA. Rossi Fanelli\u201d, Sapienza Universit\u00e0 di Roma, 00185 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Philippa","family":"Mills","sequence":"additional","affiliation":[{"name":"Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1233-9338","authenticated-orcid":false,"given":"Martino L.","family":"di Salvo","sequence":"additional","affiliation":[{"name":"Dipartimento di Scienze Biochimiche \u201cA. Rossi Fanelli\u201d, Sapienza Universit\u00e0 di Roma, 00185 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Claudio","family":"Graziani","sequence":"additional","affiliation":[{"name":"Dipartimento di Scienze Biochimiche \u201cA. Rossi Fanelli\u201d, Sapienza Universit\u00e0 di Roma, 00185 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2552-8560","authenticated-orcid":false,"given":"Victoria","family":"Bunik","sequence":"additional","affiliation":[{"name":"Belozersky Institute of Physico-Chemical Biology, Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia"},{"name":"Department of Biochemistry, Sechenov University, 119991 Moscow, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter","family":"Clayton","sequence":"additional","affiliation":[{"name":"Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5235-9993","authenticated-orcid":false,"given":"Roberto","family":"Contestabile","sequence":"additional","affiliation":[{"name":"Dipartimento di Scienze Biochimiche \u201cA. Rossi Fanelli\u201d, Sapienza Universit\u00e0 di Roma, 00185 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5625-1170","authenticated-orcid":false,"given":"Angela","family":"Tramonti","sequence":"additional","affiliation":[{"name":"Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, 00185 Rome, Italy"},{"name":"Dipartimento di Scienze Biochimiche \u201cA. Rossi Fanelli\u201d, Sapienza Universit\u00e0 di Roma, 00185 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,11,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"629","DOI":"10.1002\/jimd.12060","article-title":"Disorders affecting vitamin B","volume":"42","author":"Wilson","year":"2019","journal-title":"J. Inherit. Metab. 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