Conformation of immunoglobulins

Chothia C, A M Lesk, A Tramontano, M Levitt, S Smith-Gill, G Air, S Sheriff, E A Padlan and D Davies 1989. Conformations of Immunoglobulin Hypervariable Regions. Nature 342 877-883. 

Chothia, C., et al. Conformations of immunoglobulin hypervariable regions. Nature 343 877-883, 1989. 

Whatever the mode of attachment of SIg to cell membranes, the major portion of the Fc part of the molecule is not embedded in the phospholipid bilayer. This is also supported by the fact that CD spectra of all membrane proteins (not lymphocytes specifically) show little conformation, which, as previously mentioned, is the conformation of immunoglobulin domains. Experiments with reconstituted lymphocyte plasma membranes (Chavin and Holliman, 1975) and model membrane systems (Weissman et al., 1974) have not, in general, been very revealing. With reconstituted membranes, very little of the original membrane immunoglobulin becomes reincorporated. Liposome models were tested by... 

Chothia C, Lesk AM, Tramontano A, Levitt M, Smith-Gill SJ, Air G, Sheriff S, Padlan EA, Davies D, Tulip WR, Colman PM, Spinelli S, Alzari PM, Poljak RJ. Conformations of immunoglobulin hypervariable regions. Nature 1989 342 877-... 

Homologous proteins have similar three-dimensional structures. They contain a core region, a scaffold of secondary structure elements, where the folds of the polypeptide chains are very similar. Loop regions that connect the building blocks of the scaffolds can vary considerably both in length and in structure. From a database of known immunoglobulin structures it has, nevertheless, been possible to predict successfully the conformation of hyper-variable loop regions of antibodies of known amino acid sequence. 

AMINO ACIDS, PEPTIDES PROTEINS Recommended nomenclature and symbolism for amino acids and peptides J. Biol Chem. (1985) 260, 14-42 Biochemistry (1975) 14, 449-462 Abbreviations and symbols for the description of the conformation of polypeptide chains /. Biol Chem. (1970) 245, 6489-6497 Nomenclature of iron-sulfur proteins Eur. J. Biochem. (1979) 93, 427-430 Corrections Eur. J. Biochem. (1979) 102, 315 Nomenclature of peptide hormones J. Biol Chem. (1975) 250, 3215-3216 Nomenclature of human immunoglobulins Eur. J. Biochem. (1974) 45, 5-6 Recommended nomenclature of glycoproteins, glyco-peptides, and peptidoglycans /. Biol Chem. (1987) 262, 13-18 Recommended nomenclature of electron-transfer proteins... 

Fig. 7. —Proposed Conformation of Gal,. [The suggested binding-surface of the immunoglobulin is also shown.] Reprinted, with permission, from Ref. 54, copyright by the American Chemical Society.

Bjork, I. and Tanford, C. 1971. Gross conformation of free polypeptide chains from rabbit immunoglobulin G. I. Heavy chain. Biochemistry 10, 1271-1280. 

Paramagnetic ion probes have been successfully used to study the binding characteristics and solution conformations of a number of biochemically important molecules. These include vitamin D, (533) penicillins, (534) and the antibiotics tetracycline, (535-537) vancomycin, (632) and bacitracin. (633) Antibodies and antibody fragments (immunoglobulins, IgG) have been studied by proton relaxation enhancement methods when lanthanide ions, particularly Gd(m), are bound to the proteins. (746-748). 

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