1b1x
From Proteopedia
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STRUCTURE OF DIFERRIC MARE LACTOFERRIN AT 2.62A RESOLUTION
Overview
Lactoferrin is a monomeric glycoprotein with a molecular mass of, approximately 80 kDa. The three-dimensional structure of mare diferric, lactoferrin (mlf) has been determined at 2.6 A resolution. The protein, crystallizes in the space group P 212121with a=85.2 A, b=99.5 A, c=103.1 A, with a solvent content of 55 % (v/v). The structure was solved by the, molecular replacement method using human diferric lactoferrin as the, model. The structure has been refined using XPLOR to a final R -factor of, 0.194 for all data in the 15-2.6 A resolution range. The amino acid, sequence of mlf was determined using a cDNA method. The final refined, model comprises 5281 protein atoms, 2 Fe3+, 2 CO32-and 112 water, molecules. The overall folding of mlf is similar to that of other proteins, of the transferrin family. The protein folds into two globular lobes, N, and C. The lobes are further divided into two domains, N1 and N2, and C1, and C2. The iron-binding cleft is situated between the domains in each, lobe. The N lobe appears to be well ordered and is more stable than the C, lobe in mlf unlike in other lactoferrins, where the C lobe is the more, stable. The opening of the binding cleft in the N lobe of mlf is narrower, than those in other proteins of the transferrin family. This is very, unusual and is found only in mare lactoferrin. Apart from certain, hydrophobic interactions at the mouth of the cleft, one salt-bridge, (Lys301 . . . . . . . . Glu216) crosses between the two walls of the, cleft. The two lobes are connected covalently by a three-turn alpha-helix, involving residues 334-344. The N lobe displays a highly ordered structure, with appreciably low temperature factors. The iron coordination is more, symmetrical in the N lobe than in the C lobe. There are only 16, intermolecular hydrogen bonds in the structure of mlf.
About this Structure
1B1X is a Single protein structure of sequence from Equus caballus with FE and CO3 as ligands. This structure superseeds the now removed PDB entry 1BGR. Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of mare diferric lactoferrin at 2.6 A resolution., Sharma AK, Paramasivam M, Srinivasan A, Yadav MP, Singh TP, J Mol Biol. 1999 Jun 4;289(2):303-17. PMID:10366507
Page seeded by OCA on Tue Nov 20 11:17:06 2007
