Multivalent protein‐carbohydrate interactions are involved in the initial stages of many fundamental biological and pathological processes through lectin–carbohydrate binding. The design of high affinity ligands is therefore necessary to study, inhibit and control the processes governed through carbohydrate recognition by their lectin receptors. Carbohydrate‐functionalised gold nanoclusters (glyconanoparticles, GNPs) show promising potential as multivalent tools for studies in fundamental glycobiology research as well as biomedical applications. Here we present the synthesis and characterisation of galactose functionalised GNPs and their effectiveness as binding partners for PA‐IL lectin from Pseudomonas aeruginosa. Interactions were evaluated by hemagglutination inhibition (HIA), surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) assays. Results show that the gold nanoparticle platform displays a significant cluster glycoside effect for presenting carbohydrate ligands with almost a 3000‐fold increase in binding compared with a monovalent reference probe in free solution. The most effective GNP exhibited a dissociation constant (Kd) of 50 nM per monosaccharide, the most effective ligand of PA‐IL measured to date; another demonstration of the potential of glyco‐nanotechnology towards multivalent tools and potent anti‐adhesives for the prevention of pathogen invasion. The influence of ligand presentation density on their recognition by protein receptors is also demonstrated. 相似文献
AbstractPreparation of poly[ethylene glycol dimethacrylate (EGDMA)-glycidyl methacrylate (GMA)] cryogel and its usability for amyloglucosidase adsorption were investigated. Cryogels were prepared by cryocopolymerization technique and then functionalized by lectin concanavalin A (Con A). The synthesized cryogel was characterized by FTIR, SEM and EDX analysis and then used for adsorption of amyloglucosidase in a continuous flow system. The maximal amyloglucosidase adsorption efficiency of Con A attached cryogel was found to be as 30.50?mg/g cryogel. Con A modified cryogels were used repeatedly for 30 times without any significant decrease at the amyloglucosidase adsorption capacity. SDS-PAGE and activity studies confirmed that the desorbed amyloglucosidase was active and retained 90% of its initial activity after the adsorption/desorption processes. 相似文献
A quantitatively main molecular form ofCratylia mollis lectin, isoform 1 (iso 1) was purified by affinity chromatography on Sephadex G-75, followed by ion exchange chromatography
on CM-cellulose. Another lectin form was identified in the latter step. Iso 1 is specific for glucose/mannose, with a main
subunit of 31 kDa mol wt; the native protein is basic (pI 8.5-8.6) and the constituent polypeptides had a pI range of 5.15–7.75.
An antibody to the protein was raised in a rabbit, and the conjugate was active in an immunosorbent assay. 相似文献
Pinellia ternata lectin (PTL) extracted from the fresh juice of rhizome of pinellia ternata used as a traditional Chinese medicine facilitated the quantal release of acetylcholine (ACh) in the mouse motor nerve terminals and formed cation channels in artificial lipid bilayer. Here we report the action of PTL on presynaptic membrane currents of motor nerve terminals.The experiments were performed on the intercostal nerve triangularis sterni muscle preparations. By means of the perineurial recording, the effects of PTL on the sodium current in the preterminal part , three potassium currents and two calcium currents generated from the nerve terminals were investigated. The results show that PTL increases voltage-dependent fast Ca2+ current (ICa,f), Na+ current (INa) and Ca2+-acti-vated K+ current (IK,Ca) without action on either the voltage-dependent fast K+ current (IK,f) or the slow K+ current (IK,S). These effects are irreversible, but can be reversed by mannan, the specific binding sugar for PTL.The to 相似文献
Lectins facilitate cell–cell contact and are critical in many cellular processes. Studying lectins may help us understand the mechanisms underlying tissue regeneration. We investigated the localization of an R-type lectin in a marine annelid (Perinereis sp.) with remarkable tissue regeneration abilities. Perinereis nuntia lectin (PnL), a galactose-binding lectin with repeating Gln-X-Trp motifs, is derived from the ricin B-chain. An antiserum was raised against PnL to specifically detect a 32-kDa lectin in the crude extracts from homogenized lugworms. The antiserum detected PnL in the epidermis, setae, oblique muscle, acicula, nerve cord, and nephridium of the annelid. Some of these tissues and organs also produced Galactose (Gal) or N-acetylgalactosamine (GalNAc), which was detected by fluorescent-labeled plant lectin. These results indicated that the PnL was produced in the tissues originating from the endoderm, mesoderm, and ectoderm. Besides, the localizing pattern of PnL partially merged with the binding pattern of a fluorescent-labeled mushroom lectin that binds to Gal and GalNAc. It suggested that PnL co-localized with galactose-containing glycans in Annelid tissue; this might be the reason PnL needed to be extracted with haptenic sugar, such as d-galactose, in the buffer. Furthermore, we found that a fluorescein isothiocyanate-labeled Gal/GalNAc-binding mushroom lectin binding pattern in the annelid tissue overlapped with the localizing pattern of PnL. These findings suggest that lectin functions by interacting with Gal-containing glycoconjugates in the tissues. 相似文献
Surface modification of commercial PPBs with different saccharides is described. Surface‐glycosylated PPBs were prepared through reaction between the hydroxyl groups of poly(HEMA) and acetylated saccharides such as α‐glucose pentaacetate, β‐galactose pentaacetate, and lactose octaacetate. The modified PPBs were characterized by XPS and water contact angle measurement. It was found that the grafting degree of poly(HEMA) increases with UV irradiation time, monomer concentration, and water content in solvent. The binding degree of monosaccharides is higher than that of disaccharides. The glycosylated PPBs can selectively recognize lectins, indicating potential for protein isolation.
Selected food proteins may represent suitable markers for assessing either the presence/absence of specific food ingredients or the type and intensity of food processes. A fundamental step in the quantification of any protein marker is choosing a proper protocol for solubilizing the protein of interest. This step is particularly critical in the case of solid foods and when the protein analyte is prone to undergo intermolecular disulfide exchange reactions with itself or with other protein components in the system as a consequence of process-induced unfolding. In this frame, gluten-based systems represent matrices where a protein network is present and the biomarker proteins may be either linked to other components of the network or trapped into the network itself. The protein biomarkers considered here were wheat gluten toxic sequences for coeliac (QQPFP, R5), wheat germ agglutinin (WGA), and chicken egg ovalbumin (OVA). These proteins were considered here in the frame of three different cases dealing with processes different in nature and severity. Results from individual cases are commented as for: (1) the molecular basis of the observed behavior of the protein; (2) the design of procedure aimed at improving the recovery of the protein biomarker in a form suitable for reliable identification and quantification; (3) a critical analysis of the difficulties associated with the plain transfer of an analytical protocol from one product/process to another. Proper respect for the indications provided by the studies exemplified in this study may prevent coarse errors in assays and vane attempts at estimating the efficacy of a given treatment under a given set of conditions. The cases presented here also indicate that recovery of a protein analyte often does not depend in a linear fashion on the intensity of the applied treatment, so that caution must be exerted when attributing predictive value to the results of a particular study. 相似文献