Lactotransferrin structure

Figure 5.4 (a) Stereo ribbon representation of hFBP with Fe3+ ligands shown. 6-sheets are gold, a-helices are cyan, and other structures are dark blue, (b) N-lobe of lactotransferrin. Secondary structure elements are coloured as in hFBP, except for grey regions, which are those most different from hFBP. From Bruns et al., 1997. Reproduced by permission of Nature Publishing Group. 

Bayard investigated a number of glycoproteins (aracid glycoprotein, fetuin, lactotransferrin, transferrin, and ovomucoid) by N-deacetylation followed by deamination.176 They all gave the oligosaccharides 108 and 109, demonstrating the presence of common structural elements in these compounds. 

Fig. 9.—Structure of Glycans105 of Bovine-milk Lactotransferrin ( Red Protein ).

Spik, G., Coddeville, B., Mazurier, J., Bourne, Y., Cambillaut, C., and Montreuil, J. 1994a. Primary and three-dimensional structure of lactotransferrin (lactoferrin) glycans. Adv. Exp. Med. Biol. 357, 21-32. 

Structural comparison of the iron binding sites of N-lobe of rabbit serotransferrin, human lactotransferrin and... 

Contrary to serotransferrin receptors, little is known about the structure, physicochemical properties and gene expression of lactotransferrin receptors. Their main characteristics, which are totally different from those of serotransferrin receptors, can be summarized as follows ... 

Interestingly, the glycan primary structure of lactotransferrin extracted from human polymorphonuclear leukocytes is identical to that of the non-fucosylated diantennary... 

Fig. 11. Primary structure of the glycans from human leukocyte lactotransferrin (A) [226] and human (B,C,D) [211,227-230], Rhesus monkey (A) [231], sheep (A) [232], goat (B,C) [119,228,232], and mouse (B,C)[119, 218,233] milk lactotransferrins. E, human recombinant lactotransferrin expressed in BHK cells [234],...

Fig. 12. Primary structure of the poly-At-acetyllactosaminic glycans from human lactotransferrin [235]. R, GlcNAc(Pl -4)[Fuc(a 1 -6)]o i GlcNAc(p-N)Asn.

Fig. 14. Primary structure of diantennary glycans from cow lactotransferrin with an a-l,3-Gal residue in the terminal position [119,236] and with a GalNAc residue replacing a Gal residue.

Fig. 15. Primary structure of the glycans of the oligomannosidic type from cow [236,237] (A-D), goat (B-D) [119,232], sheep (B-D)[232] and Rhesus monkey (D)[231] milk lactotransferrins. R, GlcNAc(Pl-4)GlcNAc(pl-N)Asn.

As mentioned above (see section 2.2.1), the three-dimensional structure of the peptide chains of rabbit serotransferrin, of human and bovine lactotransferrins and of ovotrans-... 

Fig. 20. Spatial conformation (a) of a free asialoglycan and (b) of the N2-asialoglycan from human lactotransferrin, determined by X-ray diffraction [283], Numbers correspond to the numbering used in structure C of Fig. 11.

As mentioned above. X-ray diffraction of transferrin furnishes little information on the 3D-structure of the glycans and the images we have today remain largely speculative since they result from molecular modelling studies. We have represented in Fig. 21 the 3D-structure, determined by molecular modelling on the basis of X-ray diffraction data of rabbit serotransferrin [276] and of human lactotransferrin [89,92]. In rabbit serotransferrin, the single glycan linked to the peptide chain is immobilized into only... 

Fig. 21. Molecular modelling (A,B) of rabbit serotransferrin glycan and (C) of human lactotransferrin [192, 210,275] (A) 3D structure of rabbit serotransferrin (B) interaction of rabbit serotransferrin glycan in a broken-wing conformation with a peptide segment (amino acids 254 to 271) in an a-helix conformation, 7,7, Al-acetylneuraminic acid residues (see Fig. 6A). (C) 3D structure of human lactotransferrin. Arrows indicate the position of glycans.

Three-dimensional structure of lactotransferrin. Top schematic representation of the folding pattern of each lactoferrin lobe Domain I is based on a beta-sheet of four parallel and two antiparallel domains Domain II is formdd from four parallel and one antiparallel strand. Bottom stereo Ca diagram of the N lobe of lactoferrin ( ) iron atom between domain I (residues 6-90-I-) and domain II (residues 91-251) ( ) disulfide bridges ( ) carbohydrate attachment site. See Reference 39. 

Two structures [(53) and (54)1 are proposed for the unique glycan of hen egg-white ovotransferrin. A comparative study of this glycan with those of human serotransferrin and lactotransferrin reveals profound differences that could form the basis for the specificity of recognition of target cells by these glycoproteins. 

Hydrazinolysis, deamination, and methylation analysis have demonstrated that ai-acid glycoprotein, fetuin, lactotransferrin, and transferrin possess structural features in common. ... 

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