Energetics of carbohydrate binding to Momordica charantia (bitter gourd) lectin: An isothermal titration calorimetric study

Sultan, Nabil Ali Mohammed; Swamy, Musti J.

doi:10.1016/j.abb.2005.03.005

Cited by 36 publications

(26 citation statements)

References 38 publications

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“…Binding of carbohydrate ligands to TDSL increase the thermal stability of the protein as indicated by increased T m values for both transitions, suggesting that ligand binding occurs preferentially to the folded state of the lectin. Shifts of T m in presence of lactose and lactulose are higher when compared to MeβGal and GalNAc, suggesting that the second sugar moiety of these β-linked disaccharides may be involved in some additional interaction with the lectin combining site, which is similar to another cucurbit seed lectin, MCL [14]. Shift of T m is higher for MeβGal when compared to MeαGal, which is in agreement with the preference of the lectin for the β-anomeric derivatives of galactose.…”

Section: Differential Scanning Calorimetrysupporting

confidence: 78%

“…This is somewhat similar to the activity of other Cucurbitaceae seed lectins. MCL and TCSL exhibits maximum activity in the pH range from 8.0-11.0 [14,15], whereas another cucurbit seed lectin, SGSL exhibits maximum activity in the pH range of 6.0-10.0 [17]. The data presented in Fig.…”

Section: Discussionmentioning

confidence: 78%

“…In comparison, the activity of TCSL was unaffected up to about 60°C, and decreased to 50% at 70°C, indicating that it is thermally more stable than TDSL. However, TDSL appears to be more stable than MCL and SGSL, which were inactivated by incubation above 50°C and 40°C, respectively [14,15,17]. It is interesting to note that while the DSC and CD studies indicate that TDSL undergoes thermal unfolding in the temperature range of 65-70°C, the activity studies on samples incubated at different temperatures show that the lectin activity starts to decrease from 60°C onwards.…”

Section: Discussionmentioning

confidence: 94%

“…Studies on lectins from other families are fewer, and there is a need to characterize them in detail to understand their properties in detail. Our laboratory has been working on the purification and characterization of lectins from the Cucurbitaceae with respect to physicochemical properties, carbohydrate binding and hydrophobic ligand binding [13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

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Spectroscopic and differential scanning calorimetric studies on the unfolding of Trichosanthes dioica seed lectin. Similar modes of thermal and chemical denaturation

Kavitha

Swamy

2009

Glycoconj J

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Physico-chemical and unfolding studies have been carried out on Trichosanthes dioica seed lectin (TDSL). The lectin exhibited maximum activity between pH 7.0 and 10.0, which decreased steeply at lower pH. The hemagglutination activity of TDSL was unaffected in the temperature range 4-50 degrees C, but decreased rapidly at higher temperatures. Differential scanning calorimetric studies indicate that thermal unfolding of TDSL is an irreversible process, which could be described by a three-state model. The calorimetric scan recorded at pH 7.0 consists of two transitions, occurring at around 338.6 K, and 342.8 K. In the presence of carbohydrate ligands both these transitions shifted to higher temperatures, suggesting that ligand binding stabilizes the native conformation of the protein. The unfolding temperature was highest at pH 5.0 indicating that TDSL is more stable at acidic pH. Gdn.HCl induced unfolding, monitored by following changes in the intrinsic fluorescence properties of the protein, was also observed to be a three-state process involving an intermediate. CD spectroscopy indicates that the secondary and tertiary structures of TDSL are rather similar at different pH values, indicating that the lectin structure remains essentially unchanged over a wide range of pH.

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Section: Differential Scanning Calorimetrysupporting

confidence: 78%

Section: Discussionmentioning

confidence: 78%

Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Spectroscopic and differential scanning calorimetric studies on the unfolding of Trichosanthes dioica seed lectin. Similar modes of thermal and chemical denaturation

Kavitha

Swamy

2009

Glycoconj J

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“…2, C and D, and Table 3). The values for LacNAc revealed the enthalpically driven binding process common to protein-carbohydrate interactions (25)(26)(27). The ⌬H of binding was temperature-dependent, the analysis of which allowed the approximation of the change in heat capacity (⌬C p ) to be Ϫ105 (Ϯ5) cal/mol/K.…”

Section: Carbohydrate Binding Properties Of Cpcbm32 Frommentioning

confidence: 99%

The Interaction of a Carbohydrate-binding Module from a Clostridium perfringens N-Acetyl-β-hexosaminidase with Its Carbohydrate Receptor

Ficko-Blean¹,

Boraston

2006

Journal of Biological Chemistry

113

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Clostridium perfringens is a notable colonizer of the human gastrointestinal tract. This bacterium is quite remarkable for a human pathogen by the number of glycoside hydrolases found in its genome. The modularity of these enzymes is striking as is the frequent occurrence of modules having amino acid sequence identity with family 32 carbohydrate-binding modules (CBMs), often referred to as F5/8 domains. Here we report the properties of family 32 CBMs from a C. perfringens N-acetyl-␤-hexosaminidase. Macroarray, UV difference, and isothermal titration calorimetry binding studies indicate a preference for the disaccharide LacNAc (␤-D-galactosyl-1,4-␤-D-N-acetylglucosamine). The molecular details of the interaction of this CBM with galactose, LacNAc, and the type II blood group H-trisaccharide are revealed by x-ray crystallographic studies at resolutions of 1.49, 2.4, and 2.3 Å , respectively.Clostridium perfringens is a Gram-positive, spore-forming, non-motile, rod-shaped anaerobe. As a pathogen of humans, C. perfringens is often associated with gas gangrene, necrotic enteritis, and, most commonly, food poisoning (1-3). Determination of the genome sequence of C. perfringens (strain 13) (4) has revealed at least 54 open reading frames encoding putative glycoside hydrolases falling into 24 known glycoside hydrolase families (see afmb.cnrs-mrs.fr/CAZY/index.html) (5). Many encode intracellular proteins likely involved in the latter stages of sugar metabolism or proteins involved in peptidoglycan remodeling; however, roughly one-half are predicted to be secreted and are likely involved in the early stages of sugar metabolism. Although C. perfringens is most frequently thought of as a "flesh-eater," its most common niche in humans is the gastrointestinal tract. However, very few, if any, of the secreted glycoside hydrolases have predicted substrate specificities consistent with metabolism of dietary polysaccharides in the human gut making gastric mucins, highly hydrated glycoproteins comprising up to 80% carbohydrate, the most likely target of the secreted C. perfringens enzymes. Indeed, the majority of these enzymes are predicted to have specificities appropriate for the degradation of complex glycans, suggesting that this bacterium is well equipped to attack the diverse sugar structures of the mucins in this environment. Consistent with this is the mucosal necrosis associated with severe enteritis caused by C. perfringens (6), which may be in part due to the arsenal of C. perfringens glycoside hydrolases. In turn, breaking down the mucosal barrier could improve access of other toxins, such as the pore-forming cpe (C. perfringens enterotoxin), to the epithelial layer.Thirteen of the predicted C. perfringens (strain 13) glycoside hydrolases (and notably 13 glycoside hydrolases for each of the sequenced Bacteroides sp. genomes (thetaiotaomicron, fragilis YCH46, and fragilis 25285)) are highly modular and have, in addition to catalytic domains, modules with amino acid sequence identity to family 32 carbohydratebinding mod...

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Purification and physicochemical characterization of two galactose‐specific isolectins from the seeds of Trichosanthes cordata

2009

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SummaryA galactose-specific lectin has been purified from the seeds of Trichosanthes cordata by affinity chromatography on crosslinked guar gum. The affinity-eluted lectin could be resolved into two isolectins, TCA-I and TCA-II by ion-exchange chromatography on DEAE cellulose. The molecular weights of the isolectins were determined as 59 and 52 kDa by SDS-PAGE. TCA-I is a heterodimer in which the two subunits with masses of 32 and 27 kDa, are covalently connected by disulfide bonds. TCA-I and TCA-II are glycoproteins with 6.2% and 6.8% covalently bound neutral sugar, respectively. CD spectroscopic studies indicate that the two isolectins are very similar in secondary structure and contain about 8 to 10% a-helix, 37-38% b-sheet, 20% b-turns, and 32-33% unordered structures. These isolectins have similar carbohydrate specificities as revealed by hemagglutination-inhibition assays. Carbohydrate specificity, subunit size and composition, and secondary structure of TCA isolectins suggest close similarity to type-II ribosome inactivating proteins. The agglutination activity of TCA-I was found to be highest in the pH range 7.0-8.0. The lectin activity was unaffected between 0 and 408C, but decreased dramatically above 408C. Association constant for the interaction of TCA-I with lactose was determined by monitoring ligand-induced changes in the protein intrinsic fluorescence characteristics as 7.42 3 10 3 M 21 at 258C. The exposure and accessibility of the tryptophan residues of TCA-I and the effect of ligand binding on them have been probed by quenching studies employing neutral and ionic quenchers.

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Energetics of carbohydrate binding to Momordica charantia (bitter gourd) lectin: An isothermal titration calorimetric study

Cited by 36 publications

References 38 publications

Spectroscopic and differential scanning calorimetric studies on the unfolding of Trichosanthes dioica seed lectin. Similar modes of thermal and chemical denaturation

Spectroscopic and differential scanning calorimetric studies on the unfolding of Trichosanthes dioica seed lectin. Similar modes of thermal and chemical denaturation

The Interaction of a Carbohydrate-binding Module from a Clostridium perfringens N-Acetyl-β-hexosaminidase with Its Carbohydrate Receptor

Purification and physicochemical characterization of two galactose‐specific isolectins from the seeds of Trichosanthes cordata

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