Rapid affinity-purification and physicochemical characterization of pumpkin (Cucurbita maxima) phloem exudate lectin

Narahari, Akkaladevi ; Swamy, Musti J. (2010) Rapid affinity-purification and physicochemical characterization of pumpkin (Cucurbita maxima) phloem exudate lectin Bioscience Reports, 30 . pp. 341-349. ISSN 0144-8463

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Official URL: http://www.bioscirep.org/bsr/030/bsr0300341.htm

Related URL: http://dx.doi.org/10.1042/BSR20090117

Abstract

The chito-oligosaccharide-specific lectin from pumpkin (Cucurbita maxima) phloem exudate has been purified to homogeneity by affinity chromatography on chitin. After SDS/PAGE in the presence of 2-mercaptoethanol, the pumpkin phloem lectin yielded a single band corresponding to a molecular mass of 23.7 kDa, whereas ESI-MS (electrospray ionization MS) gave the molecular masses of the subunit as 24645 Da. Analysis of the CD spectrum of the protein indicated that the secondary structure of the lectin consists of 9.7% α-helix, 35.8% β-sheet, 22.5% β-turn and 32.3% unordered structure. Saccharide binding did not significantly affect the secondary and tertiary structures of the protein. The haemagglutinating activity of pumpkin phloem lectin was mostly unaffected in the temperature range 4-70 °C, but a sharp decrease was seen between 75 and 85 °C. Differential scanning calorimetric and CD spectroscopic studies suggest that the lectin undergoes a co-operative thermal unfolding process centred at approx. 81.5 °C, indicating that it is a relatively stable protein.

Item Type:Article
Source:Copyright of this article belongs to Springer.
Keywords:Affinity Chromatography; Carbohydrate Binding Protein; CD; Haemagglutinin; Secondary Structure; Thermal Unfolding
ID Code:54263
Deposited On:11 Aug 2011 11:21
Last Modified:11 Aug 2011 11:21

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