Multiple approaches to assess pectin binding to galectin-3.
Although several approaches have been used to evaluate binding of carbohydrates to lectins, results are not always comparable, especially with larger polysaccharides. Here, we quantitatively assessed and compared binding of pectin-derived polysaccharides to galectin-3 (Gal-3) using five methods: surface plasmon resonance (SPR), bio-layer interferometry (BLI), fluorescence polarization (FP), competitive fluorescence-linked immunosorbance (cFLISA), and the well-known cell-based hemagglutination assay (G3H). Our studies revealed that whereas Gal-3-pectin binding parameters determined by SPR and BLI were comparable and correlated with inhibitory potencies from the G3H assay, results using FP and cFLISA assays were highly variable and depended greatly on the probe and mass of the polysaccharide. In the cFLISA assay, for example, pectins showed no inhibition when using the DTAF-labeled asialofetuin probe, but did when using a DTAF-labeled pectin probe. And the FP approach with the DTAF-lactose probe did not work on polysaccharides and large galactan chains, although it did work well with smaller galactans. Nevertheless, even though results derived from all of these methods are in general agreement, derived KD, IC50, and MIC values do differ. Our results reflect the variability using various techniques and therefore will be useful to investigators who are developing pectin-derived Gal-3 antagonists as anti-cancer agents.
Jilin Province Key Laboratory for Chemistry and Biology of Natural Drugs in Changbai Mountain, School of Life Sciences, Northeast Normal University, Changchun 130024, PR China.
Tao
T
Zhang
Jilin Province Key Laboratory for Chemistry and Biology of Natural Drugs in Changbai Mountain, School of Life Sciences, Northeast Normal University, Changchun 130024, PR China.
Yi
Y
Zheng
Jilin Province Key Laboratory for Chemistry and Biology of Natural Drugs in Changbai Mountain, School of Life Sciences, Northeast Normal University, Changchun 130024, PR China.
Dongyang
D
Zhao
Jilin Province Key Laboratory for Chemistry and Biology of Natural Drugs in Changbai Mountain, School of Life Sciences, Northeast Normal University, Changchun 130024, PR China.
Jingmin
J
Yan
Jilin Province Key Laboratory for Chemistry and Biology of Natural Drugs in Changbai Mountain, School of Life Sciences, Northeast Normal University, Changchun 130024, PR China.
Chongliang
C
Sun
Jilin Province Key Laboratory for Chemistry and Biology of Natural Drugs in Changbai Mountain, School of Life Sciences, Northeast Normal University, Changchun 130024, PR China. Electronic address: zhouyf383@nenu.edu.cn.
Yifa
Y
Zhou
Jilin Province Key Laboratory for Chemistry and Biology of Natural Drugs in Changbai Mountain, School of Life Sciences, Northeast Normal University, Changchun 130024, PR China. Electronic address: taigh477@nenu.edu.cn.
Guihua
G
Tai
D000818:Animals; D001671:Biochemistry / Q000379:methods*; D002645:Chickens; D004797:Enzyme-Linked Immunosorbent Assay; D005454:Fluorescence Polarization; D037502:Galectin 3 / Q000378:metabolism*; D006384:Hemagglutination; D006801:Humans; D007368:Interferometry; D008970:Molecular Weight; D010368:Pectins / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D020349:Surface Plasmon Resonance
D037502:Galectin 3; D010368:Pectins
Galectin-3; Methodology; Pectin