Structural characterization of the ceruloplasmin: lactoferrin complex in solution.
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.
Sabatucci
Annalaura
A
Department of Biomedical Sciences, University of Teramo, Teramo, Italy.
Vachette
Patrice
P
Vasilyev
Vadim B
VB
Beltramini
Mariano
M
Sokolov
Alexey
A
Pulina
Maria
M
Salvato
Benedetto
B
Angelucci
Clotilde B
CB
Maccarrone
Mauro
M
Cozzani
Ivo
I
Dainese
Enrico
E
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
D012996:Solutions; D002570:Ceruloplasmin; D007781:Lactoferrin