title: Ovalbumin-related protein X is a heparin-binding ov-serpin exhibiting antimicrobial activities.
abstract: Ovalbumin family contains three proteins with high sequence similarity: ovalbumin, ovalbumin-related protein Y (OVAY), and ovalbumin-related protein X (OVAX). Ovalbumin is the major egg white protein with still undefined function, whereas the biological activity of OVAX and OVAY has not yet been explored. Similar to ovalbumin and OVAY, OVAX belongs to the ovalbumin serine protease inhibitor family (ov-serpin). We show that OVAX is specifically expressed by the magnum tissue, which is responsible for egg white formation. OVAX is also the main heparin-binding protein of egg white. This glycoprotein with a predicted reactive site at Lys(367)-His(368) is not able to inhibit trypsin, plasmin, or cathepsin G with or without heparin as a cofactor. Secondary structure of OVAX is similar to that of ovalbumin, but the three-dimensional model of OVAX reveals the presence of a cluster of exposed positive charges, which potentially explains the affinity of this ov-serpin for heparin, as opposed to ovalbumin. Interestingly, OVAX, unlike ovalbumin, displays antibacterial activities against both Listeria monocytogenes and Salmonella enterica sv. Enteritidis. These properties partly involve heparin-binding site(s) of the molecule as the presence of heparin reverses its anti-Salmonella but not its anti-Listeria potential. Altogether, these results suggest that OVAX and ovalbumin, although highly similar in sequence, have peculiar sequential and/or structural features that are likely to impact their respective biological functions.
authors.affiliation: Institut National de la Recherche Agronomique, UR83 Recherches Avicoles, Fonction et Régulation des Protéines de l'Œuf, F-37380 Nouzilly, France. srehault@tours.inra.fr
authors.forename: Sophie
authors.initials: S
authors.lastname: Réhault-Godbert
authors.forename: Valérie
authors.initials: V
authors.lastname: Labas
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Helloin
authors.forename: Virginie
authors.initials: V
authors.lastname: Hervé-Grépinet
authors.forename: Cindy
authors.initials: C
authors.lastname: Slugocki
authors.forename: Magali
authors.initials: M
authors.lastname: Berges
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Bourin
authors.forename: Aurélien
authors.initials: A
authors.lastname: Brionne
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Poirier
authors.forename: Joël
authors.initials: J
authors.lastname: Gautron
authors.forename: Franck
authors.initials: F
authors.lastname: Coste
authors.forename: Yves
authors.initials: Y
authors.lastname: Nys
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D030161:Avian Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D001483:Base Sequence; D056649:Cathepsin G / Q000037:antagonists & inhibitors; D002645:Chickens / Q000378:metabolism*; D002846:Chromatography, Affinity; D005341:Fibrinolysin / Q000037:antagonists & inhibitors; D006031:Glycosylation; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006493:Heparin / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010047:Ovalbumin / Q000378:metabolism; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D015843:Serpins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D040681:Structural Homology, Protein; D014361:Trypsin Inhibitors / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D030161:Avian Proteins; D012333:RNA, Messenger; D015843:Serpins; D014361:Trypsin Inhibitors; D006493:Heparin; D010047:Ovalbumin; D056649:Cathepsin G; D005341:Fibrinolysin
keywords: Antibacterial Proteins; Chicken Egg; Glycoprotein; Heparin Binding Protein; Innate Immunity; Protein Structure; Serpin