Secretory Proteins as Potential Semiochemical Carriers in the Horse

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• 作者：Barbara D'Innocenzo ; Anna Maria Salzano ; Chiara D'Ambrosio ; Angelo Gazzano ; Alberto Niccolini ; Carlo Sorce ; Francesca Romana Dani ; Andrea Scaloni ; Paolo Pelosi
• 刊名：Biochemistry
• 出版年：2006
• 出版时间：November 14, 2006
• 年：2006
• 卷：45
• 期：45
• 页码：13418 - 13428
• 全文大小：614K
• 年卷期：v.45,no.45(November 14, 2006)
• ISSN：1520-4995

文摘

Two soluble proteins were isolated as major secretory products of horse sweat and of theparotid gland and characterized for structural and functional properties. The first protein, lipocalin allergenEquC1, was characterized for its glycosylation sites and bound glycosidic moieties. Only one (Asn53) ofthe two putative glycosylation sites within the sequence was post-translationally modified; a differentglycosylation pattern was determined with respect to data previously reported. When purified from horsesweat, this protein contained oleamide and other organic molecules as natural ligands. Ligand bindingexperiments indicated good protein selectivity toward volatile compounds having a straight chain structureof 9-11 carbon atoms, suggesting a role of this lipocalin in chemical communication. The second protein,here reported for the first time in the horse, belongs to the group of parotid secretory proteins, part of alarge superfamily of binding proteins whose function in most cases is still unclear. This protein wassequenced and characterized for its post-translational modifications. Of the three cysteine residues present,two were involved in a disulfide bridge (Cys155-Cys198). A model, built up on the basis of similarproteins, indicated a general fold characterized by the presence of a long hydrophobic barrel. Bindingexperiments performed with a number of different organic compounds failed to identify ligands for thisprotein with a well-defined physiological role.