Canavaline

J. J. Grimaldi, B. D. Sykes 1975, (Con-canavalin A a stopped flow nuclear magnetic resonance study of conformational changes induced by Mn++, Ca++, and alpha-methyl-D-mannoside),/. Biol. Chem. 250, 1618. 

According to the PDB X-ray crystal structure 2cna, jack bean con-canavalin A contains 43.5% /1-strand, 1.7% a-helix, and 1.3% 3io-helix,... 

The backbone skeletal stretch region is rather ambiguous for /1-sheet assignments. As may be seen in the ROA spectrum of jack bean con-canavalin A (Fig. 4), there are many bands in this region, mostly positive. These bands can be rather variable in intensity, width, and wavenumber in /3-sheet proteins, which may reflect the various types of distortions found in /3-sheet. 

Wong, L. A. and Mayer, M. L. (1993) Differential modulation by cyclothiazide and con-canavalin A of desensitization at native alpha-amino-3-hydroxy-5-methyl-4-isoxazolepro-pionic. Mol. Pharmacol. 44, 504-510. 

Fig. 42. Five superimposed examples of classic /3 bulges, in stereo chymotrypsin Phe-41, Cys-42 opposite Leu-33 chymotrypsin Ala-86, Lys-87 opposite Lys-107 con-canavalin A Leu-107, Ser-108 opposite Ala-196 carbonic anhydrase C Ile-90, Gln-91 opposite Val-120 and staphylococcal nuclease lie-15, Lys-16 opposite Lys-24. Here and in Fig. 43 side chains are shown (out to Cy) only for the three positions within the bulge. At the very bottom of this figure only the backbone is shown, where the two strands overlap in this projection.

One of the earliest reported carbohydrate-mimetic peptides was the dodecapeptide DVFYPYPYASGS [10]. The peptide acts as a ligand for con-canavalin A, a lectin which binds oligosaccharides bearing terminal a-linked... 

Detailed reviews on the characterization of surfaces of single crystals of small and large biomolecules such as catalase, insulin, canavalin, etc. can be found in McPherson, 1999 and Ward, 2001. 

Purify the conjugate by affinity chromatography on Con-canavalin A Sepharose (Protocol 3.6.2.4), add glycerol to 50% final concentration and store aliquots at -20 °C. The aliquots are stable for months. 

Canavalia gladiata (Jacq.) DC C. ensiformis (L.) DC Dao Dou (Broad bean) (seed) Canavaline, canavanine, urease, gibberelin A21 gibberelin A22, canavalia gibberelin I, canavalia gibberelin II33 A tonic, bactericidal, fungicidal, stomachic. 

Canavalia gibberellin I Canavalia gibberellin II Canavaline Canavanine... 

Protein folding - Lysine antimetabolite (OTCase, TRA) [lysine antimetabolite] Protein folding — impaired by Canavaline incorporation (as Arginine analogue)... 

Y. Lvov, K. Ariga, 1. Ichinose, T. Kunitake, Layer-hy-Layer Architectures of Con-canavalin A by Means of Electrostatic and Biospecific Interactions , J. Chem. Soc., Chem. Commun., 2313 (1995)... 

FIGURE 1.10 Crystals of a variety of proteins. In (a) hexagonal prisms of beef liver catalase. In (b) crystals of oo acid glycoprotein, in (c) Fab fragments of a murine immunoglobulin, and in (d) rhombohedral crystals of the seed storage protein canavalin. 

FIGURE 6.10 In (a) are the hOl diffraction intensities from a crystal of fructose 1,6 bisphosphatase from rabbit liver having space group 1222. In (b) is the hkO plane of reflections from C2221 canavalin. In both images the checkerboard patterns produced by systematic absences resulting from the I and C centering operations are evident. 

FIGURE 6.12 In (a) is the hkO diffraction plane of a P63 canavalin crystal having sixfold symmetry, and in (b) the view along the unique axis of a rhombohedral canavalin crystal that exhibits 6mm symmetry. In neither case would one choose orthogonal axes on which to index the reflections. In (a), the natural choice would be the a and b axes indicated. In (b), two choices of hexagonal axes are reasonable, but those indicated are chosen as a and b because they correspond with the real unit cell of smallest volume. 

FIGURE 6.21 In (a), the MO diffraction plane of R3 canavalin exhibits 6mm symmetry, but because of Friedel s law it could arise as a consequence of either a true sixfold axis or a threefold axis plus the Friedel center of symmetry. In (b), the M2 image, which is along the same direction but does not contain Friedel related reflections, exhibits only threefold symmetry. This demonstrates that the crystal does in fact belong to the trigonal system and not the hexagonal system. 

FIGURE 9.11 The w = j plane of the difference Patterson map for the K2HgI4 heavy atom derivative of the hexagonal crystal form of the protein canavalin. The space group is P6, so w = is a Harker section. The derivative crystal contained two major K2HgI4 substitution sites and one minor substitution site per asymmetric unit. The Patterson peaks corresponding to those sites are marked with crosses. Note that the Patterson peak corresponding to the minor site cannot be discriminated from noise peaks in the Patterson map as is often the case. 

The sheet thus plays an important role in the structure of proteins. In some it is the main secondary structural component (e.g., con-canavalin A and Bence-Jones proteins) in others it is found in conjunction with a-helical segments and in many proteins it occurs as a mixed sheet of parallel and antiparallel strands. To date, normal-mode analy-... 

Yebra M, Klein TW, Friedman H (1992) Delta-9-tetrahydrocannabinol suppresses con-canavalin A induced increase in cytoplasmic free calcium in mouse thymocytes. Life Sci 51 151-160... 

Protein Hormones. Glycosylated insulin has been prepared (D21) and its biologic function shown to be reduced by 20%. However, the life of protein hormones in vivo is short, and so that negligible in vivo glycosylation occurs. The use of glycosylated insulin complexed to con-canavalin A in a closed-loop insulin delivery system has been described (B27) it presented stability advantages over conventional insulins in these situations. 

All the above bonding interactions are important in stabilising the globular fold. The prevalence of a-helix or fi sheet varies from one protein to another. In some proteins such as myoglobin and haemoglobin (figure 3.7) the a-helix predominates. In other proteins such as con-canavalin-A (figure 3.8) the fi sheet predominates. Usually, there exists a mixture of a and fi secondary structures. 

Figure 7.10 2-curves determined under various beam line conditions and from protein crystal Laue film data (a) SRS station 9.6 prior to mirror installation (Helliwell 1984 Helliwell et al 1989b) pea lectin. (b) SRS station 9.6 after mirror installation mercury a-amylase crystal derivative, (c) SRS station 9.7, no mirror, with 50,am aluminium filter cubic con-canavalin-A. Each curve on an arbitrary relative level. From Helliwell et al (1989a). Reproduced with the permission of the American Institute of Physics. 

In an effort to uncover anticancer active metabolites in Brazilian plants, in early 1993 we initiated active collaboration with several Brazilian natural products chemists. Out of the large number of extracts brought to our laboratory by Dr. Vanderlan da S. Bolzani and screened in our mechanism-based yeast bioassay, extracts derived from two leguminous plants were selected for further studies. Based on preliminary investigation the bioactive methanolic chloroform extract of the leaves of Cassia leptophylla which was shown to contain bioactive alkaloidal constituents was further processed for alkaloids. The alkaloid fraction thus obtained was fractionated by column chromatography on alumina, followed by Silica gel preparative TLC and reversed-phase TLC to afford seven piperidine alkaloids [55] (-)-spectaline (68), (-)-spectalinine (69), canavaline (70), leptophyllin A (71), 3-acetylleptophyllin A (72), iso-... 

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