Ovomucoid structure

Fujinaga, M., et al. Crystal and molecular structures of the complex of a-chymotrypsin with its inhibitor turkey ovomucoid third domain at 1.8 A resolution. 

Some of the multibranched complex glycans of hen ovomucoid have been analyzed by f.a.b.-m.s. together with e.i.-m.s. These glycans exhibit exceptional structural features, because their mannotriose core can be highly substituted, as shown in 25. All samples gave abundant [M+Na]" ions when analyzed as their permethylated alditols, and this permitted the... 

Dlugosz M, Antosiewicz JM, Robertson AD (2004) Constant-pH molecular dynamics study of protonation-structure relationship in a heptapeptide derived from ovomucoid third domain. Phys RevE 69 021915. 

While it is impossible to make any precise statement regarding the structure of this blood group A polysaccharide until our present investigations are more advanced, it does seem possible that the structure of the alkali-stable carbohydrate residue is of a ramified type, bearing some general relationship to that deduced for ovomucoid, which, however, is much less resistant to hydrolysis than is this blood group A polysaccharide. 

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. 

Occasionally, the branchings are incomplete and the formation of the N-acetyl-lactosamine residues is only started in outline, as in the glycans of ovotransferrin (see Fig. 15), ovalbumin (see Fig. 16), and ovomucoid (see Fig. 18). In other instances, glycan structures such as have just been described are enriched with supplementary monosaccharide residues for example, the occurrence of disialyl groups [a-NeuAc-(2—>8)-a-NeuAc], and of /3-Gal-(l- 3) residues linked to the terminal galactosyl residues, has been demonstrated in different tissues and cell membranes,114,115 and in calf-thymocyte membranes,118 respectively. 

Fig. 39. Chemical structure of the glyco amino acid extracted from ovomucoid...

The structure of gels depends on the components and the process parameters. Proteins containing over 30% hydrophobic residues form coagulum-type gels, e.g., hemoglobin and egg white albumin. The gelling-type proteins contain less hydrophobic residues and are represented by some soybean proteins, ovomucoid, and gelatin. 

Fujinaga, M., Sielecki, A. R., Read, R. J., Ardelt, W., Laskowski, M., Jr., and James, M. N. (1987). Crystal and molecular structures of the complex of alpha-chymotrypsin with its inhibitor turkey ovomucoid third domain at 1.8 A resolution. J. Mol. Biol. 195, 397-418. 

Inspection of the X-ray structures of the third domain of turkey ovomucoid inhibitor (TOMI, a 56-residue peptidic inhibitor) with HLE and the peptidic inhibitor Ace-Ala-Pro-Val-trifluoromethylketone, 1 [Xj =210 80... 

Crystal Structure of the Complex of Human Leukocyte Elastase (PMN Elastase) and the Third Domain of the Turkey Ovomucoid Inhibitor. 

In another interesting application of the TCI cycle, Li et al. [128] examined the pK of proteins. This paper represents the first attempt at predicting proteins pK values using an ab initio QM/MM description of the protein in combination with a polarizable continuum model for the solvent. Briefly, the ionizable residue of the protein is treated quanto-mechanically while the rest of the structure is represented by an MM force field. This QM/MM representation of the proteins is combined with a linearized Poisson-Boltmann equation (LPBE) description of bulk solvation. By using this procedure, the authors predicted pK of Glu 43 (4.4 units) and Lys 55 (11.3 units) in Turkey Ovomucoid third domain that are in very good agreement with the experimental values of 4.8 and 11.1 units, respectively. 

M. Fujinaga, A. R. Sielecki, R. J. Read, W. Ardelt, M. Laskowski, and M. N. G. James, /. MoL Biol., 195, 397 (1987). Crystal and Molecular Structures of the Conmiexed of a-Chymotrypsin with Its Inhibitor Turkey Ovomucoid Third Domain at 1.8 Angstroms Resolution. 

---