title: Structural characterization of the ceruloplasmin: lactoferrin complex in solution.
abstract: Ceruloplasmin is a copper protein found in vertebrate plasma, which belongs to the family of multicopper oxidases. Like transferrin of the blood plasma, lactoferrin, the iron-containing protein of human milk, saliva, tears, seminal plasma and of neutrophilic leukocytes tightly binds two ferric ions. Human lactoferrin and ceruloplasmin have been previously shown to interact both in vivo and in vitro forming a complex. Here we describe a study of the conformation of the human lactoferrin/ceruloplasmin complex in solution using small angle X-ray scattering. Our ab initio structural analysis shows that the complex has a 1:1 stoichiometry and suggests that complex formation occurs without major conformational rearrangements of either protein. Rigid-body modeling of the mutual arrangement of proteins in the complex essentially yields two families of solutions. Final discrimination is possible when integrating in the modeling process extra information translating into structural constraints on the interaction between the two partners.
authors.affiliation: Department of Biomedical Sciences, University of Teramo, Teramo, Italy.
authors.forename: Annalaura
authors.initials: A
authors.lastname: Sabatucci
authors.forename: Patrice
authors.initials: P
authors.lastname: Vachette
authors.forename: Vadim B
authors.initials: VB
authors.lastname: Vasilyev
authors.forename: Mariano
authors.initials: M
authors.lastname: Beltramini
authors.forename: Alexey
authors.initials: A
authors.lastname: Sokolov
authors.forename: Maria
authors.initials: M
authors.lastname: Pulina
authors.forename: Benedetto
authors.initials: B
authors.lastname: Salvato
authors.forename: Clotilde B
authors.initials: CB
authors.lastname: Angelucci
authors.forename: Mauro
authors.initials: M
authors.lastname: Maccarrone
authors.forename: Ivo
authors.initials: I
authors.lastname: Cozzani
authors.forename: Enrico
authors.initials: E
authors.lastname: Dainese
mesh_terms: D002570:Ceruloplasmin / Q000737:chemistry* / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007781:Lactoferrin / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D012996:Solutions; D013053:Spectrophotometry
chemical_list: D012996:Solutions; D002570:Ceruloplasmin; D007781:Lactoferrin