title: Identification by FT-ICR-MS of Camelus dromedarius α-lactalbumin variants as the result of nonenzymatic deamidation of Asn-16 and Asn-45.
abstract: Nonenzymatic deamidation of asparaginyl residues can occur spontaneously under physiological conditions principally when a glycyl residue is at the carboxyl side of Asn and leads to formation of aspartyl and isoaspartyl residues. This modification can change the biological activity of proteins or peptides and trigger an auto-immune response. The α-lactalbumins of members of the Camelidae family are the only of described α-lactalbumins that carry two AsnGly sequences. In the present study, high-resolution mass spectrometry, which enables accurate mass measurement has shown that Asn(16) and Asn(45) underwent a nonenzymatic deamidation, the sequence Asn(45)-Gly(46) being deamidated spontaneously at near-neutral and basic pH and Asn(16)-Gly(17) rather at basic pH. The 16-17 sequence was probably stabilized at near-neutral pH by hydrogen bonds according to the molecular modelisation performed with the camel protein.
authors.affiliation: Université Mouloud Mammeri, Laboratoire de Recherche de Biochimie Analytique et Biotechnologies (LABAB), Tizi Ouzou, Algeria.
authors.forename: Saliha
authors.initials: S
authors.lastname: Si Ahmed Zennia
authors.affiliation: Université Mouloud Mammeri, Laboratoire de Recherche de Biochimie Analytique et Biotechnologies (LABAB), Tizi Ouzou, Algeria.
authors.forename: Abderrahmane
authors.initials: A
authors.lastname: Mati
authors.affiliation: Université de Lorraine, Service Commun de Séquence des Protéines (SCSP), Vandœuvre-lès-Nancy F-54506, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Saulnier
authors.affiliation: ESPCI ParisTech, Spectrométrie de Masse Biologique et Protéomique (SMBP), USR3149 CNRS, Paris F-75231, France.
authors.forename: Yann
authors.initials: Y
authors.lastname: Verdier
authors.affiliation: ESPCI ParisTech, Spectrométrie de Masse Biologique et Protéomique (SMBP), USR3149 CNRS, Paris F-75231, France.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Chiappetta
authors.affiliation: Université de Lorraine, Laboratoire de Cristallographie, Résonnance Magnétique et Modélisations (CRM2), UMR 7036, Vandœuvre-lès-Nancy F-54506, France; CNRS, CRM2, UMR 7036, Vandœuvre-lès-Nancy F-54506, France.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Mulliert
authors.affiliation: Université de Lorraine, Unité de Recherche Animal et Fonctionnalités des Produits Animaux (UR AFPA), Vandœuvre-lès-Nancy F-54506, France; INRA, UR AFPA, USC 340, Vandœuvre-lès-Nancy F-54506, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Miclo
authors.affiliation: ESPCI ParisTech, Spectrométrie de Masse Biologique et Protéomique (SMBP), USR3149 CNRS, Paris F-75231, France.
authors.forename: Joëlle
authors.initials: J
authors.lastname: Vinh
authors.affiliation: Université de Lorraine, Unité de Recherche Animal et Fonctionnalités des Produits Animaux (UR AFPA), Vandœuvre-lès-Nancy F-54506, France; INRA, UR AFPA, USC 340, Vandœuvre-lès-Nancy F-54506, France. Electronic address: jean-michel.girardet@univ-lorraine.fr.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Girardet
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001216:Asparagine / Q000737:chemistry; D002162:Camelus; D015180:Electrophoresis, Gel, Two-Dimensional; D006863:Hydrogen-Ion Concentration; D007768:Lactalbumin / Q000032:analysis*; D013058:Mass Spectrometry; D008892:Milk / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D011487:Protein Conformation
chemical_list: D010455:Peptides; D001216:Asparagine; D007768:Lactalbumin
keywords: Camel milk; Camel α-lactalbumin; FT-ICR-MS; Nonenzymatic deamidation