Concanavalin structure

Figure 26.6 (a) The /3-pleated sheet secondary structure of proteins is stabilized by hydrogen bonds between parallel or antiparallel chains, (b) The structure of concanavalin A, a protein with extensive regions of antiparallel / sheets, shown as flat ribbons. 

Concanavalin A, secondary structure of. 1038-1039 Concerted reaction, 1178 Condensation reaction, 882 Condensed structure, 22 Cone cells, vision and, 504-505 Configuration. 297... 

Fig. 4. Backscattered Raman and ROA spectra of the n-helical protein human serum albumin in H20 (top pair) and the /3-sheet protein jack bean concanavalin A in acetate buffer solution at pH 5.4, together with MOLSCRIPT diagrams (Kraulis, 1991) of their X-ray crystal structures (PDB codes lao6 and 2cna). 

Multiple-ion monitoring is, however, of considerable value in structural studies, but only if model compounds of known structure are available for comparison. Such an approach has been used in the study of the carbohydrate structures of glycoproteins from different tissues.50 Separation of glycopeptides obtained from various tissues was performed on columns of concanavalin A-Sepharose. Structural analysis by multiple-ion monitoring of partially methylated, alditol acetates derived from the various fractions indicated that the glycopeptides were separated according to the linkage pattern of mannose (see Fig. 1). 

Affinity chromatography was carried out on columns prepared with lightly carboxymethylated chitin, which is known to be a poor substrate for lysozyme. Both native lysozyme and regenerated 13-105 were bound to the column at pH 7 and eluted at pH 3. As controls, the basic proteins cytochrome c and pancreatic RNase A, as well as concanavalin A and a-amylase, were not bound from the same solvent at pH 7. These findings constitute a third line of evidence for formation of native-like structure in regenerated 13-105. 

Fig. 32. Stereo drawings of particular examples of types II (a) and II (b) turns from the known protein structures, (a) Concanavalin A 43-46 (Gln-Asp-Gly-Lys) (b) car-boxypeptidase A 277-280 (Tyr-Gly-Phe-Leu).

Taken together, these results suggest that molecular recognition of the dodecapeptide by antibodies differs from its recognition by concanavahn A, and that the immunological cross-reactivity observed in some studies does not reflect structural mimicry. That molecular recognition by concanavalin A of carbohydrates and peptides differs has also been shown in structural studies. Here, the functional molecular mimicry observed with respect to different receptors should not be assumed to imply structural mimicry—the inter-molecular interactions may differ in each case. 

Fourier transform infrared/photoacoustic spectroscopy (FT-IR/PAS) can be used to evaluate the secondary structure of proteins, as demonstrated by experiments on concanavalin A, hemoglobin, lysozyme, and trypsin, four proteins having different distributions of secondary... 

Lin, S.-L., Stern, E. A., Kalb (Gilboa), A. J., and Zhang, Y. (1990). Evidence from X-ray absorption fine structure spectroscopy for significant differences in the structure of concanavalin A in solution and in the crystal. Biochemistry, 29, 3599-3603. 

Complexes, see also specific type in solution, structures, see X-ray diffraction n-Complexes, 4 178-184 Complex formation constant, outersphere, 43 46, 55 electrovalent interaction in, 3 269-270 Compressibility coefficient of activation, 42 9 Comproportionation constants, class II mixed-valence complexes, 41 290-292 Comproportionation equilibrium, 41 280-281 Compton effect, 3 172 Conantokins, calcium binding, 46 470-471 Concanavalin A, 36 61, 46 308 Concensus motif, 47 451 Concentration-proportional titrations of poly-metalates, 19 250, 251, 254 Condensation... 

Figure 13.2 The crystal structures of (a) concanavalin A and (b) the carbohydrate recognition domain of galectin-3. Residues in the carbohydrate binding sites are black.

Derewenda Z, Yariv J, Helliwell JR, Kalb AJ, Dodson EJ, Papiz MZ, Wan T, Campbell J. The structure of the saccharide-binding site of concanavalin A. EMBO J 1989 8 2189-2193. 

The structure of the (l- 2)-a-D-mannopyranan has been confirmed by methylation analysis, and its interaction with concanavalin A has been tested. Concanavalin A forms a weak complex with this oligosaccharide, and this is precipitated. Two molecules of concanavalin A must, therefore, be able to link to a sequence of two, or three, (1— 2)-a-D-mannopyranosyl residues. The polymer thus gives some insight into the steric requirements, and the size of the active site, of this lectin.120... 

B is lactate dehydrogenase (Chapter 15). The plant agglutinin concanavalin A has a quaternary structure resembling that in Fig. 7-11C. -----------... 

Western blotting has become an important, modern technique for analysis and characterization of proteins. The procedure consists of, first, the electrophoretic transfer (blotting) of proteins from polyacrylamide gels to synthetic membranes. The transferred blots are then probed using immunological detection methods to identify proteins of specific structure and/or function. In this experiment, bovine serum will be fractionated by SDS-PAGE and the proteins blotted onto a nitrocellulose membrane. Serum glycoproteins will be identified by their specific interaction with the lectin concanavalin A. 

---