Crystal structures of the peanut lectin–lactose complex at acidic pH: Retention of unusual quaternary structure, empty and carbohydrate bound combining sites, molecular mimicry and crystal packing directed by interactions at the combining site

Ravishankar, R.; Thomas, Ciza; Suguna, K.; Surolia, Avadhesha; Vijayan, M.

doi:10.1002/prot.1037

Cited by 39 publications

(39 citation statements)

References 48 publications

(55 reference statements)

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“…Con A binds molecules containing α-D-mannopyranosyl, α-D-glucopyranosyl, and sterically related residues being the most studied and characterized legume lectin [10]. PNA has specificity for D-galactose and presents multimeric structure with four identical monomers binding to carbohydrates [11].…”

Section: Introductionmentioning

confidence: 99%

Chemiluminescent Detection of Carbohydrates in the Tumoral Breast Diseases

Brustein¹,

Cavalcanti²,

Melo-Júnior³

et al. 2011

Appl Biochem Biotechnol

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Nowadays, there is an increase of investigations into the fibroadenoma, mainly because some studies have shown that the occurrence of fibroadenoma is linked to an increased risk of developing breast carcinoma. Currently, the chemiluminescence biomarkers are applied for validation methods and screening. Here, a lectin chemiluminescence is proposed as new histochemistry method to identify carbohydrates in mammary tumoral tissues. The lectins concanavalin A (Con A) and peanut agglutinin (PNA) conjugated to acridinium ester were used to characterize the glycocode of breast tissues: normal, fibroadenoma, and invasive duct carcinoma (IDC). The lectin chemiluminescence expressed in relative light units (RLU) was higher in fibroadenoma and IDC than in normal tissue for both lectins tested. The relationship RLU emission versus tissue area described a linear and hyperbolic curve for IDC and fibroadenoma, respectively, using Con A whereas hyperbolic curves for both transformed tissues using PNA. RLU was abolished by inhibiting the interaction between tissues and lectins using their specific carbohydrates: methyl-α-D: -mannoside (Con A) and galactose (PNA). The intrinsic fluorescence emission did not change with combination of the lectins (Con A/PNA) to the acridinium ester for hydrophobic residues. These results represent the lectin chemiluminescence as an alternative of histochemistry method for tumoral diagnosis in the breast.

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Section: Introductionmentioning

confidence: 99%

Chemiluminescent Detection of Carbohydrates in the Tumoral Breast Diseases

Brustein¹,

Cavalcanti²,

Melo-Júnior³

et al. 2011

Appl Biochem Biotechnol

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“…to interact with residues of the binding pocket to form a hydrogen bond network that may serve to stabilize the pocket and keep the side chains of critical residues poised to bind ligand. However, the interaction of residues of loop D with the binding pocket does not appear to be a case of peptide mimicry as has been reported for concanavalin A (37) or peanut lectin (28), because the residues of loop D do not substitute for the mannose ring. In contrast, other lectins utilize tightly bound water molecules to serve as "place-holders" for the sugar hydroxyl groups (17).…”

Section: Resultsmentioning

confidence: 72%

Twists and Turns of the Cation-dependent Mannose 6-Phosphate Receptor

Olson

Zhang

Dahms

et al. 2002

Journal of Biological Chemistry

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Mannose 6-phosphate receptors (MPRs) participate in the biogenesis of lysosomes in higher eukaryotes by transporting soluble acid hydrolases from the transGolgi network to late endosomal compartments. The receptors release their ligands into the acidic environment of the late endosome and then return to the transGolgi network to repeat the process. However, the mechanism that facilitates ligand binding and dissociation upon changes in pH is not known. We report the crystal structure of the extracytoplasmic domain of the homodimeric cation-dependent MPR in a ligand-free form at pH 6.5. A comparison of the ligand-bound and ligand-free structures reveals a significant change in quaternary structure as well as a reorganization of the binding pocket, with the most prominent change being the relocation of a loop (residues Glu 134 -Cys 141 ). The movements involved in the bound-to-free transition of the cation-dependent MPR are reminiscent of those of the oxy-to-deoxy hemoglobin transition. These results allow us to propose a mechanism by which the receptor regulates its ligand binding upon changes in pH; the pK a of Glu 133 appears to be responsible for ligand release in the acidic environment of the late endosomal compartment, and the pK a values of the sugar phosphate and His 105 are accountable for its inability to bind ligand at the cell surface where the pH is about 7.4. P-type lectins function as an essential part of the degradative pathway of higher eukaryotic organisms. A well characterized function of this receptor family is its ability to target newly synthesized acid hydrolases to the lysosome. During their transport through the Golgi complex, acid hydrolases acquire a mannose 6-phosphate (Man-6-P) 1 recognition marker on their N-linked oligosaccharides that serves as a high affinity ligand for the receptors. The resulting receptor-acid hydrolase complex is transported to late endosomal compartments. Upon encountering the lower pH of this prelysosomal compartment, the complex dissociates. The hydrolytic enzymes are then packaged into lysosomes, and the uncomplexed receptors move back to the Golgi where the process is repeated numerous times for a single receptor (1-3).The 46-kDa cation-dependent mannose 6-phosphate receptor (CD-MPR) and the 300-kDa insulin-like growth factor II/cation-independent mannose 6-phosphate receptor (IGFII/CI-MPR) are the two known members of the P-type lectin family, both of which are type I membrane glycoproteins. Carbohydrate-binding proteins have historically been divided into two subgroups. The group I carbohydrate-binding proteins, which include periplasmic transport proteins and some enzymes, typically envelop their ligands in deep pockets. In contrast, group II carbohydrate-binding proteins, which include lectins, typically bind their ligands in shallow clefts on the protein surface (4). Our recent crystallographic studies of the CD-MPR in complex with ligands containing phosphomannosyl residues reveal that this P-type lectin is unusual with respect to the architecture of i...

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“…The molecular basis of the binding properties of lactose-binding legume lectins are available only for three structures: ECL (PDB code 1GZC) [27], EcorL (PDB code 1AX1) [28] and PNA (PDB code 1CR7) [29]. Crystallographic studies on CRLII would therefore contribute to understanding the specificity of the sugar-binding features in lectins.…”

Section: Purification and Affinity Characterizationmentioning

confidence: 99%

Purification, Characterization, and Preliminary X-Ray Diffraction Analysis of a Lactose-Specific Lectin from Cymbosema roseum Seeds

Rocha

Moreno

Delatorre

et al. 2008

Appl Biochem Biotechnol

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The unique carbohydrate-binding property of lectins makes them invaluable tools in biomedical research. Here, we report the purification, partial primary structure, carbohydrate affinity characterization, crystallization, and preliminary X-ray diffraction analysis of a lactose-specific lectin from Cymbosema roseum seeds (CRLII). Isolation and purification of CRLII was performed by a single step using a Sepharose-4B-lactose affinity chromatography column. The carbohydrate affinity characterization was carried using assays for hemagglutination activity and inhibition. CRLII showed hemagglutinating activity toward rabbit erythrocytes. O-glycoproteins from mucine mucopolysaccharides showed the most potent inhibition capacity at a minimum concentration of 1.2 microg mL(-1). Protein sequencing by mass spectrometry was obtained by the digestion of CRLII with trypsin, Glu-C, and AspN. CRLII partial protein sequence exhibits 46% similarity with the ConA-like alpha chain precursor. Suitable protein crystals were obtained with the hanging-drop vapor-diffusion method with 8% ethylene glycol, 0.1 M Tris-HCl pH 8.5, and 11% PEG 8,000. The monoclinic crystals belong to space group P2(1) with unit cell parameters a = 49.4, b = 89.6, and c = 100.8 A.

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Crystal structures of the peanut lectin–lactose complex at acidic pH: Retention of unusual quaternary structure, empty and carbohydrate bound combining sites, molecular mimicry and crystal packing directed by interactions at the combining site

Cited by 39 publications

References 48 publications

Chemiluminescent Detection of Carbohydrates in the Tumoral Breast Diseases

Chemiluminescent Detection of Carbohydrates in the Tumoral Breast Diseases

Twists and Turns of the Cation-dependent Mannose 6-Phosphate Receptor

Purification, Characterization, and Preliminary X-Ray Diffraction Analysis of a Lactose-Specific Lectin from Cymbosema roseum Seeds

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