1blf

From Proteopedia

Revision as of 12:19, 18 December 2007

STRUCTURE OF DIFERRIC BOVINE LACTOFERRIN AT 2.8 ANGSTROMS RESOLUTION

Overview

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

About this Structure

1BLF is a Single protein structure of sequence from Bos taurus with NAG, FE and CO3 as ligands. Known structural/functional Sites: and . Full crystallographic information is available from OCA.

Reference

Three-dimensional structure of diferric bovine lactoferrin at 2.8 A resolution., Moore SA, Anderson BF, Groom CR, Haridas M, Baker EN, J Mol Biol. 1997 Nov 28;274(2):222-36. PMID:9398529

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