Structure of chicken plasma retinol-binding protein.
The crystal structure of the specific carrier of retinol (retinol-binding protein, RBP) purified from chicken plasma has been determined (space group P2(1)2(1)2(1), with a=46.06(5) A, b=53.56(6) A, c=73.41(8) A, and one protein molecule in the asymmetric unit). Despite being obtained from a species phylogenetically distant from mammals, chicken holoRBP has an overall structure that closely resembles the previously determined structures of mammalian holoRBPs. The lack in chicken RBP of eight carboxy-terminal amino acid residues characteristic of mammalian RBPs does not significantly affect the protein structure. A distinctive feature of the avian protein is a better definition of the loop 63-67, close to the opening of the beta-barrel cavity accommodating the retinol molecule, which is rather disordered in the structures of mammalian RBPs.
Zanotti
G
G
Department of Organic Chemistry, University of Padua and Biopolymer Research Center, CNR, Padua, Italy. giuseppe.zanotti@unipd.it
Calderone
V
V
Beda
M
M
Malpeli
G
G
Folli
C
C
Berni
R
R
D000818:Animals; D002645:Chickens / Q000097:blood*; D008958:Models, Molecular; D011228:Prealbumin / Q000737:chemistry; D011487:Protein Conformation; D012177:Retinol-Binding Proteins / Q000737:chemistry*; D054839:Retinol-Binding Proteins, Plasma; D013975:Thyroxine-Binding Proteins / Q000737:chemistry; D014961:X-Ray Diffraction
D011228:Prealbumin; D012177:Retinol-Binding Proteins; D054839:Retinol-Binding Proteins, Plasma; D013975:Thyroxine-Binding Proteins