Three-dimensional structure of diferric bovine lactoferrin at 2.8 A resolution.

摘要: The three-dimensional structure of diferric bovine lactoferrin (bLf) has been determined by X-ray crystallography in order to investigate the factors that influence iron binding and release transferrins. was solved molecular replacement, using coordinates human (hLf) as a search model, refined with data 2.8 A resolution simulated annealing (X-PLOR) restrained least squares (TNT). final model comprises 5310 protein atoms (residues 5 689), 124 carbohydrate (from ten monosaccharide units, three glycan chains), 2 Fe3+, CO32- 50 water molecules. This gives an R-factor 0.232 for 21440 reflections range 30.0 A. folding bLf molecule is essentially same hLf, but differs extent closure two domains each lobe, relative orientations lobes. Differences domain are attributed amino acid changes interface, differences lobe slightly altered packing hydrophobic patches between Changed interdomain interactions may explain lesser affinity bLf, compared lysine residues behind N-lobe site offer new insights into "dilysine trigger" mechanism proposed also notable several well-defined oligosaccharide units which demonstrate structural stabilise structure. One chain, attached Asn545, appears contribute modulate from C-lobe.