@phdthesis{oai:kitami-it.repo.nii.ac.jp:00007687,
 author = {BAI, Yuting},
 month = {Sep},
 note = {Lacquer polysaccharides, which exist in the sap of Asian lacquer tree, are highly branched acidic polysaccharides with 1,3-β-galactan backbone and glucouronic acid terminals. Lacquer polysaccharides were reported to be antitumor active and blood coagulation promoting effective, which specific activities might be caused from electrostatic attraction between negative-charged carboxyl groups from the uronic acid terminal of polysaccharides, and positive-charged amino groups from target proteins. By use of surface plasmon resonance (SPR), the interaction dynamics between the polysaccharides and proteins can be quantitatively evaluated.
Lacquer polysaccharides are usually found with two molecular weight fractions, 10 x104 and 3.0 x104Dalton in the proportion of about 25% and 75% respectively. In the previous study, the single fraction of 10x104 was reported to be degraded into 3.0 x104 after the sap was collected. The two pure fractions were first isolated in this study by using
Sephadex size exclusive chromatography. It was found that both of the two fractions show the same structure by 1H and 13C NMR characterization. It was also found that addition of ferric or ferrous ion can lead to a gelation of lacquer polysaccharides with lower molecular weights in aqueous solution, suggesting that the degradation may cause by breakage of metal-carboxyl association linkages. Appearance at 1612 cm-1 due to COO- ion of the IR spectra and alkaline degradation of 3.0 x104 fraction into 1.4x104, which halved the molecular weight, could also be a proof of existence of metal-carboxyl association.
In the dynamic study of proteins-polysaccharides interaction by SPR, poly-L-lysine as an all-positive charged polypeptide model was used to be evaluated the activity of lacquer polysaccharides and their derivatives. It was found that the interaction increased with increasing molecular weight of lacquer polysaccharides. In addition, the sulfated derivatives showed significantly high interactions with dissociation-rate constant of kd = 1.74 x10-4 [1/s], association-rate constant of ka = 4.31x104 [1/Ms] and dissociation constant of KD=4.0x104-9 [M] respectively, while original lacquer polysaccharides gave only kd = 3.54 x10-4
[1/s], ka = 4.99 x102 [1/Ms] and KD = 7.10 x10-7 [M]. These result suggest that the sulfate groups, compared to carboxyl groups give stronger attraction to amino groups, and the interaction should be the reason why sulfated lacquer polysaccharides had potent anti-HIV acctivity.
To evaluate the affection of sulfation to anti-HIV activities, lacquer polysaccharides were sulfated 1, 2 and 3 times respectively, by piperidine-N-sulfate to gives sulfated lacquer polysaccharides with different degree of sulfations. According to the amino acid sequence of V3 loop, C-terminus, and CD4-binding domain of HIV surface glycoprotein gp120 were synthesised and immobilized to the sensor chip separately. The C-terminus gave the highest response that increased with increasing the degree of sulfation.
While the association-rate constant was different from the molecular weights, degree of sulfation, and binding ligands, the dissociation-rate constant of lacquer polysaccharide derivatives was not affective so much and gave rather low values. This implies high stability of the interaction and sulfated polysaccharides were expected for long-term effectives and were possible candidates as an anti-HIV medicine in the future.},
 school = {北見工業大学},
 title = {Elucidation of interaction mechanism between lacquer polysaccharides and proteins},
 year = {2013}
}