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Cocinero EJ, Stanca-Kaposta EC, Scanlan EM, Gamblin DP, Davis BG, Simons JP. Conformational choice and selectivity in singly and multiply hydrated monosaccharides in the gas phase. Chemistry 2008; 14:8947-8955. [PMID: 18720336 DOI: 10.1002/chem.200800474] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Factors governing hydration, regioselectivity and conformational choice in hydrated carbohydrates have been examined by determining and reviewing the structures of a systematically varied set of singly and multiply hydrated monosaccharide complexes in the gas phase. This has been achieved through a combination of experiments, including infrared ion-depletion spectroscopy conducted in a supersonic jet expansion, and computation through molecular mechanics, density functional theory (DFT) and ab initio calculations. New spectroscopic and/or computational results obtained for the singly hydrated complexes of phenyl beta-D-mannopyranoside (beta-D-PhMan), methyl alpha-D-gluco- and alpha-D-galactopyranoside (alpha-D-MeGlc and alpha-D-MeGal), when coupled with those reported earlier for the singly hydrated complexes of alpha-D-PhMan, beta-D-PhGlc and beta-D-PhGal, have created a comprehensive data set, which reveals a systematic pattern of conformational preference and binding site selectivity, driven by the provision of optimal, co-operative hydrogen-bonded networks in the hydrated sugars. Their control of conformational choice and structure has been further revealed through spectroscopic and/or computational investigations of a series of multiply hydrated complexes; they include beta-D-PhMan.(H2O)2,3, which has an exocyclic hydroxymethyl group, and the doubly hydrated complex of phenyl alpha-L-fucopyranoside, alpha-L-PhFuc.(H2O)2, which does not. Despite the very large number of potential structures and binding sites, the choice is highly selective with binding invariably "focussed" around the hydroxymethyl group (when present). In beta-D-PhMan.(H2O)2,3, the bound water molecules are located exclusively on its polar face and their orientation is dictated by the (perturbed) conformation of the carbohydrate to which they are attached. The possible operation of similar rules governing the structures of hydrogen-bonded protein-carbohydrate complexes is proposed.
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Affiliation(s)
- Emilio J Cocinero
- Chemistry Department, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, UK
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102
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Kittur FS, Yu HY, Bevan DR, Esen A. Homolog of the maize beta-glucosidase aggregating factor from sorghum is a jacalin-related GalNAc-specific lectin but lacks protein aggregating activity. Glycobiology 2008; 19:277-87. [PMID: 19056785 DOI: 10.1093/glycob/cwn132] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Recently, we identified the maize beta-glucosidase aggregating factor (BGAF) as a jacalin-related lectin (JRL) and showed that its lectin domain is responsible for beta-glucosidase aggregation. By searching for BGAF homologs in sorghum, we identified and obtained an EST clone and determined its complete sequence. The predicted protein had the same modular structure as maize BGAF, shared 67% sequence identity with it, and revealed the presence of two potential carbohydrate-binding sites (GG...ATYLQ, site I and GG...GVVLD, site II). Maize BGAF1 is the only lectin from a class of modular JRLs containing an N-terminal dirigent and a C-terminal JRL domain, whose sugar specificity and beta-glucosidase aggregating activity have been studied in detail. We purified to homogeneity a BGAF homolog designated as SL (Sorghum lectin) from sorghum and expressed its recombinant version in Escherichia coli. The native protein had a molecular mass of 32 kD and was monomeric. Both native and recombinant SL-agglutinated rabbit erythrocytes, and inhibition assays indicated that SL is a GalNAc-specific lectin. Exchanging the GG...GVVLD motif in SL with that of maize BGAF1 (GG...GIAVT) had no effect on GalNAc-binding, whereas binding to Man was abolished. Substitution of Thr(293) and Gln(296) in site I to corresponding residues (Val(294) and Asp(297)) of maize BGAF1 resulted in the loss of GalNAc-binding, indicating that site I is responsible for generating GalNAc specificity in SL. Gel-shift and pull-down assays after incubating SL with maize and sorghum beta-glucosidases showed no evidence of interaction nor were any SL-protein complexes detected in sorghum tissue extracts, suggesting that the sorghum homolog does not participate in protein-protein interactions.
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Affiliation(s)
- Farooqahmed S Kittur
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
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103
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Pereira-da-Silva G, Roque-Barreira MC, Van Damme EJM. Artin M: a rational substitution for the names artocarpin and KM+. Immunol Lett 2008; 119:114-5. [PMID: 18602950 DOI: 10.1016/j.imlet.2008.06.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Accepted: 06/06/2008] [Indexed: 10/21/2022]
Abstract
The aim of the present letter is to propose a rational nomenclature for the d-mannose-binding lectin from seeds of Artocarpus integrifolia. It is justified by the existing confusion in the literature concerning the trivial names used until now to designate the lectin and by the increasing interest in its biomedical applications, specially those concerning the immunomodulation activity exerted by the lectin, triggered by the recognition of glycoconjugates on the surface of cells of the innate immunity. The new nomenclature proposed for the lectin refers to both its origin and its specificity on sugar recognition.
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104
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Gupta G, Sinha S, Surolia A. Unfolding energetics and stability of banana lectin. Proteins 2008; 72:754-60. [DOI: 10.1002/prot.21961] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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105
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Nakamura-Tsuruta S, Uchiyama N, Peumans WJ, Van Damme EJM, Totani K, Ito Y, Hirabayashi J. Analysis of the sugar-binding specificity of mannose-binding-type Jacalin-related lectins by frontal affinity chromatography - an approach to functional classification. FEBS J 2008; 275:1227-39. [DOI: 10.1111/j.1742-4658.2008.06282.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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106
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Affiliation(s)
- M Vijayan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
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107
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Guerrero GG, Moreno-Fierros L. Carrier potential properties of Bacillus thuringiensis Cry1A toxins for a diphtheria toxin epitope. Scand J Immunol 2007; 66:610-8. [PMID: 17949406 DOI: 10.1111/j.1365-3083.2007.01992.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The N-terminal half or toxic fragment of Bacillus thuringiensis Cry proteins is comprised of three structural domains. In a previous paper, we showed that this region plays an important role in the immunogenicity of the B. thuringiensis Cry proteins. Due to this ability and along with their stability it is worthy of investigating whether this region has carrier potential. To approach this, an eight amino acid hydrophobic motif in alpha-helix 7 of wild-type (WT) Cry1A toxins was exchanged for a diphtheria toxin epitope (DTB). The resultant recombinant toxins were tested for their ability to induce specific anti-Cry and anti-diphtheria toxin antibodies in mice after intraperitoneal and nasal immunization. We found that recombinant Cry1A toxins retained their ability to induce serum and mucosal anti-Cry Ab as well as IgG subclasses, although with a varied magnitude. By the systemic route, the effect of the amino acid substitution in the ratio of the IgG1/IgG2a Ab, leading in some sites toward IgG1 or IgG2a is more evident. Interestingly, mice produced specific anti-DTB IgG, and IgA after intranasal immunization. Together, our results support and show the immunogenic properties of the WT Cry1A toxins as well as its carrier potential for a DTB.
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Affiliation(s)
- G G Guerrero
- Lab de Inmunidad de Mucosas, UBIMED, FES-IZTACALA, UNAM, Tlanepantla Edo de México, Mexico.
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108
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Multiplicity of carbohydrate-binding sites in β-prism fold lectins: occurrence and possible evolutionary implications. J Biosci 2007; 32:1089-110. [DOI: 10.1007/s12038-007-0111-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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109
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Pigott CR, Ellar DJ. Role of receptors in Bacillus thuringiensis crystal toxin activity. Microbiol Mol Biol Rev 2007; 71:255-81. [PMID: 17554045 PMCID: PMC1899880 DOI: 10.1128/mmbr.00034-06] [Citation(s) in RCA: 402] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Bacillus thuringiensis produces crystalline protein inclusions with insecticidal or nematocidal properties. These crystal (Cry) proteins determine a particular strain's toxicity profile. Transgenic crops expressing one or more recombinant Cry toxins have become agriculturally important. Individual Cry toxins are usually toxic to only a few species within an order, and receptors on midgut epithelial cells have been shown to be critical determinants of Cry specificity. The best characterized of these receptors have been identified for lepidopterans, and two major receptor classes have emerged: the aminopeptidase N (APN) receptors and the cadherin-like receptors. Currently, 38 different APNs have been reported for 12 different lepidopterans. Each APN belongs to one of five groups that have unique structural features and Cry-binding properties. While 17 different APNs have been reported to bind to Cry toxins, only 2 have been shown to mediate toxin susceptibly in vivo. In contrast, several cadherin-like proteins bind to Cry toxins and confer toxin susceptibility in vitro, and disruption of the cadherin gene has been associated with toxin resistance. Nonetheless, only a small subset of the lepidopteran-specific Cry toxins has been shown to interact with cadherin-like proteins. This review analyzes the interactions between Cry toxins and their receptors, focusing on the identification and validation of receptors, the molecular basis for receptor recognition, the role of the receptor in resistant insects, and proposed models to explain the sequence of events at the cell surface by which receptor binding leads to cell death.
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Affiliation(s)
- Craig R Pigott
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
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110
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Silva-Lucca RA, Tabak M, Nascimento OR, Roque-Barreira MC, Beltramini LM. Structural and thermodynamic studies of KM+, a d-mannose binding lectin from Artocarpus integrifolia seeds. Biophys Chem 2007; 79:81-93. [PMID: 17030315 DOI: 10.1016/s0301-4622(99)00035-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/1998] [Revised: 12/02/1998] [Accepted: 03/05/1999] [Indexed: 11/28/2022]
Abstract
The KM+ lectin exhibits a novel and unusual circular dichroism (CD) spectrum that could be explained by a high proline content that would be inducing deformation of the beta-structure and/or unusual turns. KM+ was shown to be a very rigid lectin, which was very stable under a broad variety of conditions (urea, guanidine, hydrolysis, pH, etc.). Only incubation for 60 min at 333-338 K and extreme basic pH were able to induce conformational changes which could be observed by CD and fluorescence measurements. Data from CD are typical for protein denaturing associated with changes in the overall secondary structure. Data from high-performance size exclusion chromatography (SEC) showed that the denatured forms produced at pH 12.0 are eluted in clusters that co-elute with the native forms. A significant contribution from the tyrosines to the fluorescence emission upon denaturation was observed above 328 K. In fact at 328 K some broadening of the emission spectrum takes place followed by the appearance of a shoulder (approx. 305 nm) at 333 K and above. The sensitivity of tryptophan fluorescence to the addition of sugar suggests a close proximity of the tryptophan residues to the sugar binding site, K(a)=(2.9+/-0.6)x10(3) M(-1). The fraction of chromophore accessible to the quencher obtained is f(a)=0.43+/-0.08, suggesting that approximately 50% of the tryptophan residues are not accessible to quenching by d-mannose. KM+ thermal denaturation was found to be irreversible and was analyzed using a two-state model (N-->D). The results obtained for the activation energy and transition temperature from the equilibrium CD studies were: activation energy, E(a)=134+/-11 kJ/mol and transition temperature, T(m)=339+/-1 K, and from the fluorescence data: E(a)=179+/-18 kJ/mol and T(m)=337+/-1 K. Kinetic studies gave the following values: E(a)=108+/-18 kJ/mol and E(a)=167+/-12 kJ/mol for CD and fluorescence data, respectively.
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Affiliation(s)
- R A Silva-Lucca
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, São Carlos, SP, Brazil
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111
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Naeem A, Ahmad E, Ashraf MT, Khan RH. Purification and characterization of mannose/glucose-specific lectin from seeds of Trigonella foenumgraecum. BIOCHEMISTRY (MOSCOW) 2007; 72:44-8. [PMID: 17309436 DOI: 10.1134/s0006297907010051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A lectin present in seeds of Trigonella foenumgraecum was isolated and purified by acid precipitation, salt fractionation, and affinity chromatography on mannan cross-linked agarose. SDS-PAGE revealed a single band corresponding to a molecular weight of 27,350 daltons. The lectin agglutinated trypsin-treated rat erythrocytes. Sugar specificity as determined by hemagglutination inhibition assay indicated that the lectin belongs to a glucose/mannose-specific group. The reaction of the lectin with glycoprotein was affected by pH changes. The carbohydrate binding specificity of the lectin was investigated by turbidity and activity measurements. As the lectin belongs to the Leguminoceae family, the specificity of the lectin for glucose/mannose renders it a valuable tool for Rhizobium-legume symbiosis.
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Affiliation(s)
- Aabgeena Naeem
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, 202002, India
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112
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Guerrero GG, Russell WM, Moreno-Fierros L. Analysis of the cellular immune response induced by Bacillus thuringiensis Cry1A toxins in mice: Effect of the hydrophobic motif from diphtheria toxin. Mol Immunol 2007; 44:1209-17. [PMID: 16930715 DOI: 10.1016/j.molimm.2006.06.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Revised: 06/13/2006] [Accepted: 06/15/2006] [Indexed: 11/21/2022]
Abstract
Insecticidal Cry1A toxins from Bacillus thuringiensis elicit strong humoral immune response in mice. Previously, we showed that an eight hydrophobic motif amino acid substitution in Domain I did not affect the antibody inducing capacity of the Cry1A toxins, on the contrary, it was enhanced after intranasal immunization. In addition, Cry1A mutants (carrying a substitution of a motif from fragment B of diphtheria toxin into the structurally similar hydrophobic alpha-helix 7 motif of Cry1A toxins) were able to modulate the ratio of IgG subclasses, IgG1/IgG2a. However, the capacity of these toxins to induce cellular immune response has not been studied. Thus, in this work, we investigated the cytokine profile induced after in vitro stimulation with the toxins, in spleen cell cultures from unprimed mice, and intranasally primed mice, with either wild-type Cry1Aa or with mutant toxin Cry1Aa8. Spleen cells from unprimed mice stimulated with Cry1Aa produced very low levels of Th1 (IFN-gamma, IL-12p70) and Th2 type cytokines (IL-10, IL-4), whereas immunization with Cry1Aa8 toxin led to higher production of these cytokines. Restimulation of spleen cells from primed mice with the Cry1Aa induced the production of significant levels of IL-12p70 whereas with Cry1Aa8, IFN-gamma production was stimulated. Interestingly, we found that the capacity of Cry1A toxins to induce cytokine production by lymphocytes was inhibited by N-acetylgalactosamine. Altogether these data demonstrate the immunogenic properties of Cry1A toxins and show that amino acid substitution in Domain I principally affects its ability to induce Th1 cytokines in lymphocytes.
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Affiliation(s)
- G G Guerrero
- Unidad de Biomedicina Immunidad en Mucosas, FES-Iztacala, Universidad Nacional Autónoma de México. Av de los Barrios No 1 Los Reyes Iztacala CP 54090,Tlanepantla, Estado de México, México.
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113
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Kittur FS, Lalgondar M, Yu HY, Bevan DR, Esen A. Maize beta-glucosidase-aggregating factor is a polyspecific jacalin-related chimeric lectin, and its lectin domain is responsible for beta-glucosidase aggregation. J Biol Chem 2007; 282:7299-311. [PMID: 17210577 DOI: 10.1074/jbc.m607417200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In certain maize genotypes, called "null," beta-glucosidase does not enter gels and therefore cannot be detected on zymograms after electrophoresis. Such genotypes were originally thought to be homozygous for a null allele at the glu1 gene and thus devoid of enzyme. We have shown that a beta-glucosidase-aggregating factor (BGAF) is responsible for the "null" phenotype. BGAF is a chimeric protein consisting of two distinct domains: the disease response or "dirigent" domain and the jacalin-related lectin (JRL) domain. First, it was not known whether the lectin domain in BGAF is functional. Second, it was not known which of the two BGAF domains is involved in beta-glucosidase binding and aggregation. To this end, we purified BGAF to homogeneity from a maize null inbred line called H95. The purified protein gave a single band on SDS-PAGE, and the native protein was a homodimer of 32-kDa monomers. Native and recombinant BGAF (produced in Escherichia coli) agglutinated rabbit erythrocytes, and various carbohydrates and glycoproteins inhibited their hemagglutination activity. Sugars did not have any effect on the binding of BGAF to the beta-glucosidase isozyme 1 (Glu1), and the BGAF-Glu1 complex could still bind lactosyl-agarose, indicating that the sugar-binding site of BGAF is distinct from the beta-glucosidase-binding site. Neither the dirigent nor the JRL domains alone (produced separately in E. coli) produced aggregates of Glu1 based on results from pull-down assays. However, gel shift and competitive binding assays indicated that the JRL domain binds beta-glucosidase without causing it to aggregate. These results with those from deletion mutagenesis and replacement of the JRL domain of a BGAF homolog from sorghum, which does not bind Glu1, with that from maize allowed us to conclude that the JRL domain of BGAF is responsible for its lectin and beta-glucosidase binding and aggregating activities.
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Affiliation(s)
- Farooqahmed S Kittur
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0406, USA
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114
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Natchiar SK, Suguna K, Surolia A, Vijayan M. Peanut agglutinin, a lectin with an unusual quaternary structure and interesting ligand binding properties. CRYSTALLOGR REV 2007. [DOI: 10.1080/08893110701382087] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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115
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Abstract
A paper in this issue of Structure reports the crystal structure of griffithsin, a lectin from red algae, and demonstrates its ability to bind and neutralize the SARS coronavirus, providing a link in understanding the evolution of lectins in this family. (Ziółkowska et al., 2006).
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Affiliation(s)
- Nagasuma Chandra
- Bioinformatics Centre, Indian Institute of Science, Bangalore, 560012, India
- Ph: +91-80-22932892; Fax:+91-80-23600551
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116
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Abstract
3dSS is a web-based interactive computing server, primarily designed to aid researchers, to superpose two or several 3D protein structures. In addition, the server can be effectively used to find the invariant and common water molecules present in the superposed homologous protein structures. The molecular visualization tool RASMOL is interfaced with the server to visualize the superposed 3D structures with the water molecules (invariant or common) in the client machine. Furthermore, an option is provided to save the superposed 3D atomic coordinates in the client machine. To perform the above, users need to enter Protein Data Bank (PDB)-id(s) or upload the atomic coordinates in PDB format. This server uses a locally maintained PDB anonymous FTP server that is being updated weekly. This program can be accessed through our Bioinformatics web server at the URL or .
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Affiliation(s)
- K. Sumathi
- Bioinformatics Centre, Indian Institute of ScienceBangalore 560 012, India
| | - P. Ananthalakshmi
- Bioinformatics Centre, Indian Institute of ScienceBangalore 560 012, India
| | | | - K. Sekar
- Bioinformatics Centre, Indian Institute of ScienceBangalore 560 012, India
- Supercomputer Education and Research Centre, Indian Institute of ScienceBangalore 560 012, India
- To whom correspondence should be addressed. Tel: +91 080 23601409; Fax: +91 080 23600085; ,
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117
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Boonserm P, Mo M, Angsuthanasombat C, Lescar J. Structure of the functional form of the mosquito larvicidal Cry4Aa toxin from Bacillus thuringiensis at a 2.8-angstrom resolution. J Bacteriol 2006; 188:3391-401. [PMID: 16621834 PMCID: PMC1447447 DOI: 10.1128/jb.188.9.3391-3401.2006] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Cry4Aa delta-endotoxin from Bacillus thuringiensis is toxic to larvae of Culex, Anopheles, and Aedes mosquitoes, which are vectors of important human tropical diseases. With the objective of designing modified toxins with improved potency that could be used as biopesticides, we determined the structure of this toxin in its functional form at a resolution of 2.8 angstroms. Like other Cry delta-endotoxins, the activated Cry4Aa toxin consists of three globular domains, a seven-alpha-helix bundle responsible for pore formation (domain I) and the following two other domains having structural similarities with carbohydrate binding proteins: a beta-prism (domain II) and a plant lectin-like beta-sandwich (domain III). We also studied the effect on toxicity of amino acid substitutions and deletions in three loops located at the surface of the putative receptor binding domain II of Cry4Aa. Our results indicate that one loop is an important determinant of toxicity, presumably through attachment of Cry4Aa to the surface of mosquito cells. The availability of the Cry4Aa structure should guide further investigations aimed at the molecular basis of the target specificity and membrane insertion of Cry endotoxins.
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Affiliation(s)
- Panadda Boonserm
- Institute of Molecular Biology and Genetics, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand.
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118
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Singh T, Wu JH, Peumans WJ, Rougé P, Van Damme EJM, Wu AM. Recognition profile of Morus nigra agglutinin (Morniga G) expressed by monomeric ligands, simple clusters and mammalian polyvalent glycotopes. Mol Immunol 2006; 44:451-62. [PMID: 16581130 DOI: 10.1016/j.molimm.2006.02.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Accepted: 02/21/2006] [Indexed: 11/25/2022]
Abstract
The carbohydrate binding properties of a novel member of the subfamily of galactose-specific jacalin-related lectin isolated from the bark of black mulberry (Morus nigra) (Morniga G) was studied in detail by enzyme-linked lectinosorbent and inhibition assays using panels of monomeric saccharides, mammalian polyvalent glycotopes and polysaccharides. Among the natural glycans tested for lectin binding, Morniga G reacted best with glycoproteins (gps) presenting a high density of tumor-associated carbohydrate antigens Tn (GalNAcalpha1-Ser/Thr) and Talpha (Galbeta1-3GalNAcalpha1-). Their reactivities, on a nanogram basis, were up to 72.5, 3.9x10(3), 6.0x10(3), 8.8x10(3) and 2.9x10(4) times higher than that of Tn-containing glycopeptides (M.W.<3000 Da), monomeric T, Tn, GalNAc and Gal, respectively. It also reacted well with many multi-antennary N-glycans with II (Galbeta1-4GlcNAc) termini, ABH histo-blood group antigens and their precursors containing high densities of I/II and T/Tn glycotopes, and sialylated T/Tn. Among the mono-, di- and oligosaccharides tested, Thomsen-Friedenreich (T) disaccharide with aromatic aglycon [Galbeta1-3GalNAcalpha1-benzyl (Talpha1-benzyl)] and Tn glycopeptides were the best inhibitors. Molecular modeling and docking studies indicated the occurrence of a primary GalNAcalpha1- and Galbeta1-3GalNAc glycotope-binding site in Morniga G. Using a recently proposed system [Wu, A.M., 2003. Carbohydrate structural units in glycoproteins and polysaccharides as important ligands for Gal and GalNAc reactive lectins. J. Biomed. Sci. 10, 676-688], the binding properties of the combining sites of Morniga G can be defined as follows: (i) the monosaccharide specificity is GalNAc/Gal>>Man/Glc, GlcNAc and lFuc; (ii) the mammalian glycotope specificity is Talpha1-benzyl>T>Tn>GalNAcbeta1-3Gal (P), while B/E (Galalpha1-3/4Gal), I/II (Galbeta1-3/4GlcNAc), S (GalNAcbeta1-4Gal), F/A (GalNAcalpha1-3GalNAc/Gal) and L (Galbeta1-4Glc) are inactive; (iii) the most active ligand is T/Tn; (iv) simple clustered Tn or triantennary N-glycans with II termini (Tri-II) have limited impact; (v) high-density polyvalent glycotopes play a prominent role for enhancing Morniga G reactivity. These results provide evidence for the binding of this lectin to dense cell surface T/Tn glycoconjugates and facilitate future usage of this lectin in biotechnological and medical applications.
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Affiliation(s)
- Tanuja Singh
- Glyco-Immunochemistry Research Laboratory, Institute of Molecular and Cellular Biology, Chang-Gung University, Kwei-san, Tao-yuan 333, Taiwan
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119
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Dube DH, Prescher JA, Quang CN, Bertozzi CR. Probing mucin-type O-linked glycosylation in living animals. Proc Natl Acad Sci U S A 2006; 103:4819-24. [PMID: 16549800 PMCID: PMC1405625 DOI: 10.1073/pnas.0506855103] [Citation(s) in RCA: 158] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2005] [Indexed: 11/18/2022] Open
Abstract
Changes in O-linked protein glycosylation are known to correlate with disease states but are difficult to monitor in a physiological setting because of a lack of experimental tools. Here, we report a technique for rapid profiling of O-linked glycoproteins in living animals by metabolic labeling with N-azidoacetylgalactosamine (GalNAz) followed by Staudinger ligation with phosphine probes. After injection of mice with a peracetylated form of GalNAz, azide-labeled glycoproteins were observed in a variety of tissues, including liver, kidney, and heart, in serum, and on isolated splenocytes. B cell glycoproteins were robustly labeled with GalNAz but T cell glycoproteins were not, suggesting fundamental differences in glycosylation machinery or metabolism. Furthermore, GalNAz-labeled B cells could be selectively targeted with a phosphine probe by Staudinger ligation within the living animal. Metabolic labeling with GalNAz followed by Staudinger ligation provides a means for proteomic analysis of this posttranslational modification and for identifying O-linked glycoprotein fingerprints associated with disease.
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Affiliation(s)
| | | | | | - Carolyn R. Bertozzi
- Departments of *Chemistry and
- Molecular and Cell Biology and
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720; and
- Molecular Foundry, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
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Ralph S, Park JY, Bohlmann J, Mansfield SD. Dirigent proteins in conifer defense: gene discovery, phylogeny, and differential wound- and insect-induced expression of a family of DIR and DIR-like genes in spruce (Picea spp.). PLANT MOLECULAR BIOLOGY 2006; 60:21-40. [PMID: 16463097 DOI: 10.1007/s11103-005-2226-y] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Accepted: 08/17/2005] [Indexed: 05/06/2023]
Abstract
The outer stem tissues of conifers provide a durable constitutive and inducible defense barrier consisting of suberized or lignified periderm, sclereids, a network of terpenoid-filled resin ducts, and phenolic phloem parenchyma cells. Microarray gene expression profiling of Sitka spruce (Picea sitchensis) bark attacked by stem-boring weevils (Pissodes strobi) or through mechanical wounding demonstrated significant accumulation of transcripts resembling dirigent protein (DIR) genes. To investigate this gene family and its spatial and temporal patterns of expression in conifer defense, we isolated cDNAs representing 19 unique DIR and DIR-like genes from Sitka spruce, white spruce (P. glauca), and interior spruce (P. glauca x engelmannii). Sequence alignments also identified a large number of DIR-like proteins in other plant species, which share several conserved protein motifs with known DIR proteins. Phylogenetic analysis of 72 DIR and DIR-like proteins suggests five distinct subfamilies, DIR-a and four DIR-like subfamilies (DIR-b, DIR-c, DIR-d and DIR-e). Previously characterized members of the DIR-a subfamily direct stereoselective phenolic coupling reactions in the formation of lignans and possibly lignins. The spruce genes identified here are members of the DIR-a and DIR-b subfamilies. Using gene-specific quantitative real-time PCR we measured constitutive expression for six DIR-a genes and three DIR-like genes in different stem tissues, green shoot tips, and roots of Sitka spruce. DIR-like genes revealed ubiquitous high expression in all tissues. In contrast, the six DIR-a genes showed a gradient of transcript abundance in stem tissues with highest levels in the outer cortex and lowest levels in the inner xylem. Gene-specific transcript profiling of six DIR-a genes confirmed rapid and strong accumulation (up to 500-fold) in wound- and weevil-induced stem bark and xylem. These findings suggest a role for spruce DIR genes in constitutive and induced phenolic defense mechanisms against stem-boring insects.
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Affiliation(s)
- Steven Ralph
- Michael Smith Laboratories, University of British Columbiad, V6T1Z4, Vancouver, BC, Canada
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121
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Komath SS, Kavitha M, Swamy MJ. Beyond carbohydrate binding: new directions in plant lectin research. Org Biomol Chem 2006; 4:973-88. [PMID: 16525538 DOI: 10.1039/b515446d] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Although for a long time carbohydrate binding property has been used as the defining feature of lectins, studies carried out mostly during the last two decades or so demonstrate that many plant lectins exhibit specific interactions with small molecules that are predominantly hydrophobic in nature. Such interactions, in most cases, appear to be at specific sites that do not interfere with the ability of the lectins to recognise and bind carbohydrates. Further, several of these ligands have binding affinities comparable to those for the binding of specific carbohydrates to the lectins. Given the ability of lectins to specifically recognise the glycocode (carbohydrate code) on different cell surfaces and distinguish between diseased and normal tissues, these additional sites may be viewed as potential drug carrying sites that could be exploited for targeted delivery to sites of choice. Porphyrin-lectin complexes are especially suited for such targeting since porphyrins are already under investigation in photodynamic therapy for cancer. This review will provide an update on the interactions of plant lectins with non-carbohydrate ligands, with particular emphasis on porphyrin ligands. The implications and potential applications of such studies will also be discussed.
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Affiliation(s)
- Sneha Sudha Komath
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India.
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Rabijns A, Barre A, Van Damme EJM, Peumans WJ, De Ranter CJ, Rougé P. Structural analysis of the jacalin-related lectin MornigaM from the black mulberry (Morus nigra) in complex with mannose. FEBS J 2005; 272:3725-32. [PMID: 16008570 DOI: 10.1111/j.1742-4658.2005.04801.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The structures of MornigaM and the MornigaM-mannose complex have been determined at 1.8 A and 2.0 A resolution, respectively. Both structures adopt the typical beta-prism motif found in other jacalin-related lectins and their tetrameric assembly closely resembles that of jacalin. The carbohydrate-binding cavity of MornigaM readily binds mannose. No major structural rearrangements can be observed in MornigaM upon binding of mannose. These results allow corroboration of the structure-function relationships within the small group of Moraceae lectins.
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Affiliation(s)
- Anja Rabijns
- Laboratory of Analytical Chemistry and Medicinal Physicochemistry, Faculty of Pharmaceutical Sciences, K. U. Leuven, Belgium
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123
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Gallego del Sol F, Nagano C, Cavada BS, Calvete JJ. The first crystal structure of a Mimosoideae lectin reveals a novel quaternary arrangement of a widespread domain. J Mol Biol 2005; 353:574-83. [PMID: 16185708 DOI: 10.1016/j.jmb.2005.08.055] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2005] [Revised: 08/22/2005] [Accepted: 08/23/2005] [Indexed: 11/16/2022]
Abstract
The crystal structures of the apo and mannose-bound Parkia platycephala seed lectin represent the first structure of a Mimosoideae lectin and a novel circular arrangement of beta-prism domains, and highlight the adaptability of the beta-prism fold as a building block in the evolution of plant lectins. The P.platycephala lectin is a dimer both in solution and in the crystals. Mannose binding to each of the three homologous carbohydrate-recognition domains of the lectin occurs through different modes, and restrains the flexibility of surface-exposed loops and residues involved in carbohydrate recognition. The planar array of carbohydrate-binding sites on the rim of the toroid-shaped structure of the P.platycephala lectin dimer immediately suggests a mechanism to promote multivalent interactions leading to cross-linking of carbohydrate ligands as part of the host strategy against phytopredators and pathogens. The cyclic structure of the P.platycephala lectin points to the convergent evolution of a structural principle for the construction of lectins involved in host defense or in attacking other organisms.
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124
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Nakamura S, Yagi F, Totani K, Ito Y, Hirabayashi J. Comparative analysis of carbohydrate-binding properties of two tandem repeat-type Jacalin-related lectins, Castanea crenata agglutinin and Cycas revoluta leaf lectin. FEBS J 2005; 272:2784-99. [PMID: 15943812 DOI: 10.1111/j.1742-4658.2005.04698.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lectins belonging to the jacalin-related lectin family are distributed widely in the plant kingdom. Recently, two mannose-specific lectins having tandem repeat-type structures were discovered in Castanea crenata (angiosperm) and Cycas revoluta (gymnosperm). The occurrence of such similar molecules in taxonomically less related plants suggests their importance in the plant body. To obtain clues to understand their physiological roles, we performed detailed analysis of their sugar-binding specificity. For this purpose, we compared the dissociation constants (K(d)) of Castanea crenata agglutinin (CCA) and Cycas revoluta leaf lectin (CRLL) by using 102 pyridylaminated and 13 p-nitrophenyl oligosaccharides with a recently developed automated system for frontal affinity chromatography. As a result, we found that the basic carbohydrate-binding properties of CCA and CRLL were similar, but differed in their preference for larger N-linked glycans (e.g. Man7-9 glycans). While the affinity of CCA decreased with an increase in the number of extended alpha1-2 mannose residues, CRLL could recognize these Man7-9 glycans with much enhanced affinity. Notably, both lectins also preserved considerable affinity for mono-antennary, complex type N-linked glycans, though the specificity was much broader for CCA. The information obtained here should be helpful for understanding their functions in vivo as well as for development of useful probes for animal cells. This is the first systematic approach to elucidate the fine specificities of plant lectins by means of high-throughput, automated frontal affinity chromatography.
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Affiliation(s)
- Sachiko Nakamura
- Glycostructure Analysis Team, Research Center for Glycoscience, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan
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125
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Olson R, Gouaux E. Crystal Structure of the Vibrio cholerae Cytolysin (VCC) Pro-toxin and its Assembly into a Heptameric Transmembrane Pore. J Mol Biol 2005; 350:997-1016. [PMID: 15978620 DOI: 10.1016/j.jmb.2005.05.045] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 05/10/2005] [Accepted: 05/12/2005] [Indexed: 11/25/2022]
Abstract
Pathogenic Vibrio cholerae secrete V. cholerae cytolysin (VCC), an 80 kDa pro-toxin that assembles into an oligomeric pore on target cell membranes following proteolytic cleavage and interaction with cell surface receptors. To gain insight into the activation and targeting activities of VCC, we solved the crystal structure of the pro-toxin at 2.3A by X-ray diffraction. The core cytolytic domain of VCC shares a fold similar to the staphylococcal pore-forming toxins, but in VCC an amino-terminal pro-domain and two carboxy-terminal lectin domains decorate the cytolytic domain. The pro-domain masks a protomer surface that likely participates in inter-protomer interactions in the cytolytic oligomer, thereby explaining why proteolytic cleavage and movement of the pro-domain is necessary for toxin activation. A single beta-octyl glucoside molecule outlines a possible receptor binding site on one lectin domain, and removal of this domain leads to a tenfold decrease in lytic activity toward rabbit erythrocytes. VCC activated by proteolytic cleavage assembles into an oligomeric species upon addition of soybean asolectin/cholesterol liposomes and this oligomer was purified in detergent micelles. Analytical ultracentrifugation and crystallographic analysis indicate that the resulting VCC oligomer is a heptamer. Taken together, these studies define the architecture of a pore forming toxin and associated lectin domains, confirm the stoichiometry of the assembled oligomer as heptameric, and suggest a common mechanism of assembly for staphylococcal and Vibrio cytolytic toxins.
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Affiliation(s)
- Rich Olson
- Department of Biochemistry and Molecular Biophysics, Columbia University, 650 W. 168th Street, New York, NY 10032, USA
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126
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Singh DD, Saikrishnan K, Kumar P, Surolia A, Sekar K, Vijayan M. Unusual sugar specificity of banana lectin from Musa paradisiaca and its probable evolutionary origin. Crystallographic and modelling studies. Glycobiology 2005; 15:1025-32. [PMID: 15958419 DOI: 10.1093/glycob/cwi087] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The crystal structure of a complex of methyl-alpha-D-mannoside with banana lectin from Musa paradisiaca reveals two primary binding sites in the lectin, unlike in other lectins with beta-prism I fold which essentially consists of three Greek key motifs. It has been suggested that the fold evolved through successive gene duplication and fusion of an ancestral Greek key motif. In other lectins, all from dicots, the primary binding site exists on one of the three motifs in the three-fold symmetric molecule. Banana is a monocot, and the three motifs have not diverged enough to obliterate sequence similarity among them. Two Greek key motifs in it carry one primary binding site each. A common secondary binding site exists on the third Greek key. Modelling shows that both the primary sites can support 1-2, 1-3, and 1-6 linked mannosides with the second residue interacting in each case primarily with the secondary binding site. Modelling also readily leads to a bound branched mannopentose with the nonreducing ends of the two branches anchored at the two primary binding sites, providing a structural explanation for the lectin's specificity for branched alpha-mannans. A comparison of the dimeric banana lectin with other beta-prism I fold lectins, provides interesting insights into the variability in their quaternary structure.
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Affiliation(s)
- D D Singh
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, Karnataka, India
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127
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Meagher JL, Winter HC, Ezell P, Goldstein IJ, Stuckey JA. Crystal structure of banana lectin reveals a novel second sugar binding site. Glycobiology 2005; 15:1033-42. [PMID: 15944373 DOI: 10.1093/glycob/cwi088] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Banana lectin (Banlec) is a dimeric plant lectin from the jacalin-related lectin family. Banlec belongs to a subgroup of this family that binds to glucose/mannose, but is unique in recognizing internal alpha1,3 linkages as well as beta1,3 linkages at the reducing termini. Here we present the crystal structures of Banlec alone and with laminaribiose (LAM) (Glcbeta1, 3Glc) and Xyl-beta1,3-Man-alpha-O-Methyl. The structure of Banlec has a beta-prism-I fold, similar to other family members, but differs from them in its mode of sugar binding. The reducing unit of the sugar is inserted into the binding site causing the second saccharide unit to be placed in the opposite orientation compared with the other ligand-bound structures of family members. More importantly, our structures reveal the presence of a second sugar binding site that has not been previously reported in the literature. The residues involved in the second site are common to other lectins in this family, potentially signaling a new group of mannose-specific jacalin-related lectins (mJRL) with two sugar binding sites.
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128
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Botos I, Wlodawer A. Proteins that bind high-mannose sugars of the HIV envelope. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2005; 88:233-82. [PMID: 15572157 DOI: 10.1016/j.pbiomolbio.2004.05.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A broad range of proteins bind high-mannose carbohydrates found on the surface of the envelope protein gp120 of the human immunodeficiency virus and thus interfere with the viral life cycle, providing a potential new way of controlling HIV infection. These proteins interact with the carbohydrate moieties in different ways. A group of them interacts as typical C-type lectins via a Ca2+ ion. Another group interacts with specific single, terminal sugars, without the help of a metal cation. A third group is involved in more intimate interactions, with multiple carbohydrate rings and no metal ion. Finally, there is a group of lectins for which the interaction mode has not yet been elucidated. This review summarizes, principally from a structural point of view, the current state of knowledge about these high-mannose binding proteins and their mode of sugar binding.
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Affiliation(s)
- Istvan Botos
- Macromolecular Crystallography Laboratory, National Cancer Institute, NCI-Frederick, Building 536, Room 5, Frederick, MD 21702-1201, USA
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129
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Carrizo ME, Capaldi S, Perduca M, Irazoqui FJ, Nores GA, Monaco HL. The Antineoplastic Lectin of the Common Edible Mushroom (Agaricus bisporus) Has Two Binding Sites, Each Specific for a Different Configuration at a Single Epimeric Hydroxyl. J Biol Chem 2005; 280:10614-23. [PMID: 15596442 DOI: 10.1074/jbc.m411989200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The lectin from the common mushroom Agaricus bisporus, the most popular edible species in Western countries, has potent antiproliferative effects on human epithelial cancer cells, without any apparent cytotoxicity. This property confers to it an important therapeutic potential as an antineoplastic agent. The three-dimensional structure of the lectin was determined by x-ray diffraction. The protein is a tetramer with 222 symmetry, and each monomer presents a novel fold with two beta sheets connected by a helix-loop-helix motif. Selectivity was studied by examining the binding of four monosaccharides and seven disaccharides in two different crystal forms. The T-antigen disaccharide, Galbeta1-3GalNAc, mediator of the antiproliferative effects of the protein, binds at a shallow depression on the surface of the molecule. The binding of N-acetylgalactosamine overlaps with that moiety of the T antigen, but surprisingly, N-acetylglucosamine, which differs from N-acetylgalactosamine only in the configuration of epimeric hydroxyl 4, binds at a totally different site on the opposite side of the helix-loop-helix motif. The lectin thus has two distinct binding sites per monomer that recognize the different configuration of a single epimeric hydroxyl. The structure of the protein and its two carbohydrate-binding sites are described in detail in this study.
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Affiliation(s)
- Maria E Carrizo
- Biocrystallography Laboratory, Department of Science and Technology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy
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130
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Arockia Jeyaprakash A, Jayashree G, Mahanta SK, Swaminathan CP, Sekar K, Surolia A, Vijayan M. Structural basis for the energetics of jacalin-sugar interactions: promiscuity versus specificity. J Mol Biol 2005; 347:181-8. [PMID: 15733927 DOI: 10.1016/j.jmb.2005.01.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Revised: 12/29/2004] [Accepted: 01/05/2005] [Indexed: 11/21/2022]
Abstract
Jacalin, a tetrameric lectin, is one of the two lectins present in jackfruit (Artocarpus integrifolia) seeds. Its crystal structure revealed, for the first time, the occurrence of the beta-prism I fold in lectins. The structure led to the elucidation of the crucial role of a new N terminus generated by post-translational proteolysis for the lectin's specificity for galactose. Subsequent X-ray studies on other carbohydrate complexes showed that the extended binding site of jacalin consisted of, in addition to the primary binding site, a hydrophobic secondary site A composed of aromatic residues and a secondary site B involved mainly in water-bridges. A recent investigation involving surface plasmon resonance and the X-ray analysis of a methyl-alpha-mannose complex, had led to a suggestion of promiscuity in the lectin's sugar specificity. To explore this suggestion further, detailed isothermal titration calorimetric studies on the interaction of galactose (Gal), mannose (Man), glucose (Glc), Me-alpha-Gal, Me-alpha-Man, Me-alpha-Glc and other mono- and oligosaccharides of biological relevance and crystallographic studies on the jacalin-Me-alpha-Glc complex and a new form of the jacalin-Me-alpha-Man complex, have been carried out. The binding affinity of Me-alpha-Man is 20 times weaker than that of Me-alpha-Gal. The corresponding number is 27, when the binding affinities of Gal and Me-alpha-Gal, and those of Man and Me-alpha-Man are compared. Glucose (Glc) shows no measurable binding, while the binding affinity of Me-alpha-Glc is slightly less than that of Me-alpha-Man. The available crystal structures of jacalin-sugar complexes provide a convincing explanation for the energetics of binding in terms of interactions at the primary binding site and secondary site A. The other sugars used in calorimetric studies show no detectable binding to jacalin. These results and other available evidence suggest that jacalin is specific to O-glycans and its affinity to N-glycans is extremely weak or non-existent and therefore of limited value in processes involving biological recognition.
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131
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Ananthalakshmi P, Samayamohan K, Chokalingam C, Mayilarasi C, Sekar K. PSST-2.0: Protein Data Bank Sequence Search Tool. APPLIED BIOINFORMATICS 2005; 4:141-5. [PMID: 16128616 DOI: 10.2165/00822942-200504020-00008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
UNLABELLED PSST-2.0 (Protein Data Bank [PDB] Sequence Search Tool) is an updated version of the earlier PSST (Protein Sequence Search Tool), and the philosophy behind the search engine has remained unchanged. PSST-2.0 is a Web-based, interactive search engine developed to retrieve required protein or nucleic acid sequence information and some of its related details, primarily from sequences derived from the structures deposited in the PDB (the database of 3-dimensional [3-D] protein and nucleic acid structures). Additionally, the search engine works for a selected subset of 25% or 90% non-homologous protein chains. For some of the selected options, the search engine produces a detailed output for the user-uploaded, 3-D atomic coordinates of the protein structure (PDB file format) from the client machine through the Web browser. The search engine works on a locally maintained PDB, which is updated every week from the parent server at the Research Collaboratory for Structural Bioinformatics, and hence the search results are up to date at any given time. AVAILABILITY PSST-2.0 is freely accessible via http://pranag.physics.iisc.ernet.in/psst/ or http://144.16.71.10/psst/.
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132
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Guerrero GG, Dean DH, Moreno-Fierros L. Structural implication of the induced immune response by Bacillus thuringiensis Cry proteins: role of the N-terminal region. Mol Immunol 2004; 41:1177-83. [PMID: 15482853 DOI: 10.1016/j.molimm.2004.06.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Indexed: 11/29/2022]
Abstract
The potential role of the regions (carboxil and amino) of the Cry proteins in the ability of these proteins to elicit strong immune responses was investigated. Intraperitoneal immunization of mice with the homologous Cry1A protoxins (130-133 kDa), with the long C-terminal half gave rise mostly to similar, strong serum and mucosal IgG and IgM antibody response but a lower induction of these Ab by intranasal route. Remarkably, Cry3A protoxin, devoid of C-terminal half was able to induce a significant mucosal IgG, and IgM Ab as well as Cry1A protoxins, suggesting us that immunogenic abilities are not restricted to C-terminal half but N-terminal half itself could be involved. In fact, this assumption was strengthen by the strong immunogenic abilities of the Cry1A toxins, specially IgG and IgA Ab induced by both routes in different mucosal sites. These data indicate that immunogenic abilities of the Bt Cry proteins reside and depends of the N-terminal half.
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Affiliation(s)
- Gloria Guillermina Guerrero
- FES-IZTACALA, Universidad Nacional Autónoma de México, Biomedicine Av de los Barrios s/n Col. Los Reyes Iztacala 54090 Tlanepantla, Edo de México, Mexico.
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133
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Barre A, Peumans WJ, Rossignol M, Borderies G, Culerrier R, Van Damme EJM, Rougé P. Artocarpin is a polyspecific jacalin-related lectin with a monosaccharide preference for mannose. Biochimie 2004; 86:685-91. [PMID: 15556279 DOI: 10.1016/j.biochi.2004.09.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2004] [Accepted: 09/02/2004] [Indexed: 11/25/2022]
Abstract
A reinvestigation of the carbohydrate-binding properties revealed that artocarpin, a previously described mannose-specific lectin from jackfruit (Artocarpus integrifolia) seeds, behaves as a polyspecific lectin. Surface plasmon resonance hapten inhibition experiments demonstrated that artocarpin readily interacted with a wide range of monosaccharides covering galactose, N-acetylgalactosamine, mannose, glucose, sialic acid and N-acetylmuramic acid. Molecular docking confirmed this unexpected ability of artocarpin to interact with structurally different sugars. The biological significance of the polyspecificity of the lectin is discussed in terms of the broadening of the range of potential target glycans present on the surface of plant phytopathogens or predators.
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Affiliation(s)
- Annick Barre
- Surfaces Cellulaires et Signalisation chez les Végétaux, UMR-CNRS 5546, Pôle de Biotechnologie Végétale, 24 chemin de Borde-Rouge, BP 17, Auzeville, 31326 Castanet-Tolosan, France
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134
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Pereyra A, Zenteno R, Vázquez L, Martínez-Cairo S, Rodríguez A, Mendoza-Hernández G, Zenteno E, Agundis C. Characterization of lectin aggregates in the hemolymph of freshwater prawn Macrobrachium rosenbergii. Biochim Biophys Acta Gen Subj 2004; 1673:122-30. [PMID: 15279883 DOI: 10.1016/j.bbagen.2004.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2004] [Revised: 04/08/2004] [Accepted: 04/08/2004] [Indexed: 12/12/2022]
Abstract
In invertebrates, lectins play relevant roles in innate immunity; however, their regulatory mechanisms have not been identified yet. In this work, we purified, by gel filtration and affinity chromatography, lectin aggregates circulating in the hemolymph of the freshwater prawn Macrobrachium rosenbergii and compared their physicochemical properties with a previously described lectin (MrL). High-molecular weight MrL aggregates (MrL-I) lack hemagglutinating activity and showed bands of 62.1, 67.1 and 81.4 kDa, whereas MrL-III, which corresponds to MrL, showed hemagglutinating activity and is constituted by a single 9.6-kDa band as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. MrL-I and MrL-III showed similar amino acid composition but different carbohydrates concentration. Edman degradation indicated NH2-terminal sequence of five amino acids for the 9.6-kDa MrL-III (DVPLL/A) and eleven for the main 81.4-kDa band identified in MrL-I (DVPLL/AXKQQQD); analysis by MALDI-TOF indicated a different tryptic pattern for MrL-I and MrL-III. MrL-I was recognized by monoclonal antibodies against MrL-III. Circular dichroism indicated that the secondary structure in both proteins is similar and contains 23% of beta-sheet and 24% of alpha-helix. Our results suggest that differential posttranslational processes that favor aggregation are involved in regulating the activity of the lectin.
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Affiliation(s)
- Ali Pereyra
- Departamento de Bioquímica, Instituto Nacional de Enfermedades Respiratorias, 10245, Mexico
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135
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Jeyaprakash AA, Srivastav A, Surolia A, Vijayan M. Structural Basis for the Carbohydrate Specificities of Artocarpin: Variation in the Length of a Loop as a Strategy for Generating Ligand Specificity. J Mol Biol 2004; 338:757-70. [PMID: 15099743 DOI: 10.1016/j.jmb.2004.03.040] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Revised: 03/05/2004] [Accepted: 03/10/2004] [Indexed: 11/18/2022]
Abstract
Artocarpin, a tetrameric lectin of molecular mass 65 kDa, is one of the two lectins extracted from the seeds of jackfruit. The structures of the complexes of artocarpin with mannotriose and mannopentose reported here, together with the structures of artocarpin and its complex with Me-alpha-mannose reported earlier, show that the lectin possesses a deep-seated binding site formed by three loops. The binding site can be considered as composed of two subsites; the primary site and the secondary site. Interactions at the primary site composed of two of the loops involve mainly hydrogen bonds, while those at the secondary site comprising the third loop are primarily van der Waals in nature. Mannotriose in its complex with the lectin interacts through all the three mannopyranosyl residues; mannopentose interacts with the protein using at least three of the five mannose residues. The complexes provide a structural explanation for the carbohydrate specificities of artocarpin. A detailed comparison with the sugar complexes of heltuba, the only other mannose-specific jacalin-like lectin with known three-dimensional structure in sugar-bound form, establishes the role of the sugar-binding loop constituting the secondary site, in conferring different specificities at the oligosaccharide level. This loop is four residues longer in artocarpin than in heltuba, providing an instance where variation in loop length is used as a strategy for generating carbohydrate specificity.
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136
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Hang HC, Yu C, Ten Hagen KG, Tian E, Winans KA, Tabak LA, Bertozzi CR. Small Molecule Inhibitors of Mucin-Type O-Linked Glycosylation from a Uridine-Based Library. ACTA ACUST UNITED AC 2004; 11:337-45. [PMID: 15123263 DOI: 10.1016/j.chembiol.2004.02.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2003] [Revised: 11/10/2003] [Accepted: 12/12/2003] [Indexed: 10/26/2022]
Abstract
The polypeptide N-acetyl-alpha-galactosaminyltransferases (ppGalNAcTs, also abbreviated ppGaNTases) initiate mucin-type O-linked glycosylation and therefore play pivotal roles in cell-cell communication and protection of tissues. In order to develop new tools for studying mucin-type O-linked glycosylation, we screened a 1338 member uridine-based library to identify small molecule inhibitors of ppGalNAcTs. Using a high-throughput enzyme-linked lectin assay (ELLA), two inhibitors of murine ppGalNAcT-1 (K(I) approximately 8 microM) were identified that also inhibit several other members of the family. The compounds did not inhibit other mammalian glycosyltransferases or nucleotide sugar utilizing enzymes, suggesting selectivity for the ppGalNAcTs. Treatment of cells with the compounds abrogated mucin-type O-linked glycosylation but not N-linked glycosylation and also induced apoptosis. These uridine analogs represent the first generation of chemical tools to study the functions of mucin-type O-linked glycosylation.
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Affiliation(s)
- Howard C Hang
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA
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137
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Sujatha MS, Balaji PV. Identification of common structural features of binding sites in galactose-specific proteins. Proteins 2004; 55:44-65. [PMID: 14997539 DOI: 10.1002/prot.10612] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Galactose-binding proteins characterize an important subgroup of sugar-binding proteins that are involved in a variety of biological processes. Structural studies have shown that the Gal-specific proteins encompass a diverse range of primary and tertiary structures. The binding sites for galactose also seem to vary in different protein-galactose complexes. No common binding site features that are shared by the Gal-specific proteins to achieve ligand specificity are so far known. With the assumption that common recognition principles will exist for common substrate recognition, the present study was undertaken to identify and characterize any unique galactose-binding site signature by analyzing the three-dimensional (3D) structures of 18 protein-galactose complexes. These proteins belong to 7 nonhomologous families; thus, there is no sequence or structural similarity across the families. Within each family, the binding site residues and their relative distances were well conserved, but there were no similarities across families. A novel, yet simple, approach was adopted to characterize the binding site residues by representing their relative spatial dispositions in polar coordinates. A combination of the deduced geometrical features with the structural characteristics, such as solvent accessibility and secondary structure type, furnished a potential galactose-binding site signature. The signature was evaluated by incorporation into the program COTRAN to search for potential galactose-binding sites in proteins that share the same fold as the known galactose-binding proteins. COTRAN is able to detect galactose-binding sites with a very high specificity and sensitivity. The deduced galactose-binding site signature is strongly validated and can be used to search for galactose-binding sites in proteins. PROSITE-type signature sequences have also been inferred for galectin and C-type animal lectin-like fold families of Gal-binding proteins.
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Affiliation(s)
- M S Sujatha
- School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
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138
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Knight PJK, Carroll J, Ellar DJ. Analysis of glycan structures on the 120 kDa aminopeptidase N of Manduca sexta and their interactions with Bacillus thuringiensis Cry1Ac toxin. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2004; 34:101-112. [PMID: 14976987 DOI: 10.1016/j.ibmb.2003.09.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The Bacillus thuringiensis Cry1Ac toxin specifically binds to a 120 kDa aminopeptidase N (APN) receptor in Manduca sexta. The binding interaction is mediated by GalNAc, presumably covalently attached to the APN as part of an undefined glycan structure. Here we detail a simple, rapid and specific chemical deglycosylation technique, applicable to glycoproteins immobilized on Western blots. We used the technique to directly and unambiguously demonstrate that carbohydrates attached to 120 kDA APN are in fact binding epitopes for Cry1Ac toxin. This technique is generally applicable to all putative Cry toxin/receptor combinations. We analyzed the various glycans on the 120 kDA APN using carbohydrate compositional analysis and lectin binding. The data indicate that in the average APN molecule, 2 of 4 possible N-glycosylation sites are occupied with fucosylated paucimannose [Man(2-3)(Fuc(1-2)GlcNAc(2)-peptide] type N-glycans. Additionally, we identified 13 probable O-glycosylation sites, 10 of which are located in the Thr/Pro rich C-terminal "stalk" region of the protein. It is likely that 5-6 of the 13 sites are occupied, probably with simple [GalNAc-peptide] type O-glycans. This O-glycosylated C-terminal stalk, being GalNAc-rich, is the most likely binding site for Cry1Ac.
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Affiliation(s)
- Peter J K Knight
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
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139
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Hang HC, Yu C, Kato DL, Bertozzi CR. A metabolic labeling approach toward proteomic analysis of mucin-type O-linked glycosylation. Proc Natl Acad Sci U S A 2003; 100:14846-51. [PMID: 14657396 PMCID: PMC299823 DOI: 10.1073/pnas.2335201100] [Citation(s) in RCA: 389] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mucin-type O-linked glycoproteins are involved in a variety of biological interactions in higher eukaryotes. The biosynthesis of these glycoproteins is initiated by a family of polypeptide N-acetyl-alpha-galactosaminyltransferases (ppGalNAcTs) that modify proteins in the secretory pathway. The lack of a defined consensus sequence for the ppGalNAcTs makes the prediction of mucin-type O-linked glycosylation difficult based on primary sequence alone. Herein we present a method for labeling mucin-type O-linked glycoproteins with a unique chemical tag, the azide, which permits their selective covalent modification from complex cell lysates. From a panel of synthetic derivatives, we identified an azido GalNAc analog (N-azidoacetylgalactosamine, GalNAz) that is metabolized by numerous cell types and installed on mucin-type O-linked glycoproteins by the ppGalNAcTs. The azide serves as a bioorthogonal chemical handle for selective modification with biochemical or biophysical probes using the Staudinger ligation. The approach was validated by labeling a recombinant glycoprotein that is known to possess O-linked glycans with GalNAz. In addition, GalNAz efficiently labeled mucin-type O-linked glycoproteins expressed at endogenous levels. The ability to label mucin-type O-linked glycoproteins with chemical tags should facilitate their identification by proteomic strategies.
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Affiliation(s)
- Howard C Hang
- Center for New Directions in Organic Synthesis and Department of Chemistry, University of California, Berkeley, CA 94720-1460, USA
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140
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Bourne Y, Roig-Zamboni V, Barre A, Peumans WJ, Astoul CH, Van Damme EJM, Rougé P. The crystal structure of the Calystegia sepium agglutinin reveals a novel quaternary arrangement of lectin subunits with a beta-prism fold. J Biol Chem 2003; 279:527-33. [PMID: 14561768 DOI: 10.1074/jbc.m308218200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The high number of quaternary structures observed for lectins highlights the important role of these oligomeric assemblies during carbohydrate recognition events. Although a large diversity in the mode of association of lectin subunits is frequently observed, the oligomeric assemblies of plant lectins display small variations within a single family. The crystal structure of the mannose-binding jacalin-related lectin from Calystegia sepium (Calsepa) has been determined at 1.37-A resolution. Calsepa exhibits the same beta-prism fold as identified previously for other members of the family, but the shape and the hydrophobic character of its carbohydrate-binding site is unlike that of other members, consistent with surface plasmon resonance analysis showing a preference for methylated sugars. Calsepa reveals a novel dimeric assembly markedly dissimilar to those described earlier for Heltuba and jacalin but mimics the canonical 12-stranded beta-sandwich dimer found in legume lectins. The present structure exemplifies the adaptability of the beta-prism building block in the evolution of plant lectins and highlights the biological role of these quaternary structures for carbohydrate recognition.
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Affiliation(s)
- Yves Bourne
- AFMB-CNRS, CNRS UMR6098, F13402 Marseille Cedex 20, France.
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141
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Jeyaprakash AA, Katiyar S, Swaminathan CP, Sekar K, Surolia A, Vijayan M. Structural basis of the carbohydrate specificities of jacalin: an X-ray and modeling study. J Mol Biol 2003; 332:217-28. [PMID: 12946359 DOI: 10.1016/s0022-2836(03)00901-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The structures of the complexes of tetrameric jacalin with Gal, Me-alpha-GalNAc, Me-alpha-T-antigen, GalNAcbeta1-3Gal-alpha-O-Me and Galalpha1-6Glc (mellibiose) show that the sugar-binding site of jacalin has three components: the primary site, secondary site A, and secondary site B. In these structures and in the two structures reported earlier, Gal or GalNAc occupy the primary site with the anomeric carbon pointing towards secondary site A. The alpha-substituents, when present, interact, primarily hydrophobically, with secondary site A which has variable geometry. O-H..., centered pi and C-H...pi hydrogen bonds involving this site also exist. On the other hand, beta-substitution leads to severe steric clashes. Therefore, in complexes involving beta-linked disaccharides, the reducing sugar binds at the primary site with the non-reducing end located at secondary site B. The interactions at secondary site B are primarily through water bridges. Thus, the nature of the linkage determines the mode of the association of the sugar with jacalin. The interactions observed in the crystal structures and modeling based on them provide a satisfactory qualitative explanation of the available thermodynamic data on jacalin-carbohydrate interactions. They also lead to fresh insights into the nature of the binding of glycoproteins by jacalin.
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Affiliation(s)
- A Arockia Jeyaprakash
- Molecular Biophysics Unit, UGC Centre of Advanced Study, Indian Institute of Science, Bangalore 560 012, India
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142
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Hussain ASZ, Kumar CK, Rajesh CK, Sheik SS, Sekar K. SEM (Symmetry Equivalent Molecules): A web-based GUI to generate and visualize the macromolecules. Nucleic Acids Res 2003; 31:3356-8. [PMID: 12824326 PMCID: PMC168993 DOI: 10.1093/nar/gkg587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
SEM, Symmetry Equivalent Molecules, is a web-based graphical user interface to generate and visualize the symmetry equivalent molecules (proteins and nucleic acids). In addition, the program allows the users to save the three-dimensional atomic coordinates of the symmetry equivalent molecules in the local machine. The widely recognized graphics program RasMol has been deployed to visualize the reference (input atomic coordinates) and the symmetry equivalent molecules. This program is written using CGI/Perl scripts and has been interfaced with all the three-dimensional structures (solved using X-ray crystallography) available in the Protein Data Bank. The program, SEM, can be accessed over the World Wide Web interface at http://dicsoft2.physics.iisc.ernet.in/sem/ or http://144.16.71.11/sem/.
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Affiliation(s)
- A S Z Hussain
- Bioinformatics Centre, Supercomputer Education and Research Centre, Indian Institute of Science, Bangalore, 560 012, India
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143
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A structural basis for the difference in specificity between the two jacalin-related lectins from mulberry (Morus nigra) bark. Biochem Biophys Res Commun 2003; 304:91-7. [PMID: 12705889 DOI: 10.1016/s0006-291x(03)00538-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The activity and specificity of a galactose-specific and a mannose-specific jacalin-related lectin from the bark of the black mulberry (Morus nigra) tree has been re-investigated using different experimental approaches. Both lectins definitely behave as polyspecific lectins recognizing galactose, mannose, and glucose even though MornigaG and MornigaM interact preferentially with galactose and mannose, respectively. The exceptionally extended size of the carbohydrate-binding site of both lectins apparently accounts for their polyspecific character. Parallel studies with other mannose-specific jacalin-related lectins confirmed that their exclusive specificity towards mannose/glucose relies on a reduced size of their carbohydrate-binding site.
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144
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Jurat-Fuentes JL, Gould FL, Adang MJ. Altered Glycosylation of 63- and 68-kilodalton microvillar proteins in Heliothis virescens correlates with reduced Cry1 toxin binding, decreased pore formation, and increased resistance to Bacillus thuringiensis Cry1 toxins. Appl Environ Microbiol 2002; 68:5711-7. [PMID: 12406769 PMCID: PMC129908 DOI: 10.1128/aem.68.11.5711-5717.2002] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The binding and pore formation abilities of Cry1A and Cry1Fa Bacillus thuringiensis toxins were analyzed by using brush border membrane vesicles (BBMV) prepared from sensitive (YDK) and resistant (YHD2) strains of Heliothis virescens. 125I-labeled Cry1Aa, Cry1Ab, and Cry1Ac toxins did not bind to BBMV from the resistant YHD2 strain, while specific binding to sensitive YDK vesicles was observed. Binding assays revealed a reduction in Cry1Fa binding to BBMV from resistant larvae compared to Cry1Fa binding to BBMV from sensitive larvae. In agreement with this reduction in binding, neither Cry1A nor Cry1Fa toxin altered the permeability of membrane vesicles from resistant larvae, as measured by a light-scattering assay. Ligand blotting experiments performed with BBMV and 125I-Cry1Ac did not differentiate sensitive larvae from resistant larvae. Iodination of BBMV surface proteins suggested that putative toxin-binding proteins were exposed on the surface of the BBMV from resistant insects. BBMV protein blots probed with the N-acetylgalactosamine-specific lectin soybean agglutinin (SBA) revealed altered glycosylation of 63- and 68-kDa glycoproteins but not altered glycosylation of known Cry1 toxin-binding proteins in YHD2 BBMV. The F1 progeny of crosses between sensitive and resistant insects were similar to the sensitive strain when they were tested by toxin-binding assays, light-scattering assays, and lectin blotting with SBA. These results are evidence that a dramatic reduction in toxin binding is responsible for the increased resistance and cross-resistance to Cry1 toxins observed in the YHD2 strain of H. virescens and that this trait correlates with altered glycosylation of specific brush border membrane glycoproteins.
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145
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Houlès Astoul C, Peumans WJ, van Damme EJM, Barre A, Bourne Y, Rougé P. The size, shape and specificity of the sugar-binding site of the jacalin-related lectins is profoundly affected by the proteolytic cleavage of the subunits. Biochem J 2002; 367:817-24. [PMID: 12169094 PMCID: PMC1222947 DOI: 10.1042/bj20020856] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2002] [Revised: 07/17/2002] [Accepted: 08/08/2002] [Indexed: 11/17/2022]
Abstract
Mannose-specific lectins with high sequence similarity to jacalin and the Maclura pomifera agglutinin have been isolated from species belonging to the families Moraceae, Convolvulaceae, Brassicaceae, Asteraceae, Poaceae and Musaceae. Although these novel mannose-specific lectins are undoubtedly related to the galactose-specific Moraceae lectins there are several important differences. Apart from the obvious differences in specificity, the mannose- and galactose-specific jacalin-related lectins differ in what concerns their biosynthesis and processing, intracellular location and degree of oligomerization of the protomers. Taking into consideration that the mannose-specific lectins are widely distributed in higher plants, whereas their galactose-specific counterparts are confined to a subgroup of the Moraceae sp. one can reasonably assume that the galactose-specific Moraceae lectins are a small-side group of the main family. The major change that took place in the structure of the binding site of the diverging Moraceae lectins concerns a proteolytic cleavage close to the N-terminus of the protomer. To corroborate the impact of this change, the specificity of jacalin was re-investigated using surface plasmon resonance analysis. This approach revealed that in addition to galactose and N -acetylgalactosamine, the carbohydrate-binding specificity of jacalin extends to mannose, glucose, N -acetylmuramic acid and N -acetylneuraminic acid. Owing to this broad carbohydrate-binding specificity, jacalin is capable of recognizing complex glycans from plant pathogens or predators.
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Affiliation(s)
- Corinne Houlès Astoul
- Institut de Pharmacologie et Biologie Structurale, UMR-CNRS 5089, 205 Route de Narbonne, 31077 Toulouse Cedex 4, France
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146
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Van Damme EJM, Hause B, Hu J, Barre A, Rougé P, Proost P, Peumans WJ. Two distinct jacalin-related lectins with a different specificity and subcellular location are major vegetative storage proteins in the bark of the black mulberry tree. PLANT PHYSIOLOGY 2002; 130:757-69. [PMID: 12376642 PMCID: PMC166604 DOI: 10.1104/pp.005892] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2002] [Revised: 04/17/2002] [Accepted: 06/18/2002] [Indexed: 05/21/2023]
Abstract
Using a combination of protein isolation/characterization and molecular cloning, we have demonstrated that the bark of the black mulberry tree (Morus nigra) accumulates large quantities of a galactose-specific (MornigaG) and a mannose (Man)-specific (MornigaM) jacalin-related lectin. MornigaG resembles jacalin with respect to its molecular structure, specificity, and co- and posttranslational processing indicating that it follows the secretory pathway and eventually accumulates in the vacuolar compartment. In contrast, MornigaM represents a novel type of highly active Man-specific jacalin-related lectin that is synthesized without signal peptide or other vacuolar targeting sequences, and accordingly, accumulates in the cytoplasm. The isolation and cloning, and immunocytochemical localization of MornigaG and MornigaM not only demonstrates that jacalin-related lectins act as vegetative storage proteins in bark, but also allows a detailed comparison of a vacuolar galactose-specific and a cytoplasmic Man-specific jacalin-related lectin from a single species. Moreover, the identification of MornigaM provides the first evidence, to our knowledge, that bark cells accumulate large quantities of a cytoplasmic storage protein. In addition, due to its high activity, abundance, and ease of preparation, MornigaM is of great potential value for practical applications as a tool and bioactive protein in biological and biomedical research.
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Affiliation(s)
- Els J M Van Damme
- Laboratory for Phytopathology and Plant Protection, Catholic University Leuven, 2001 Leuven, Belgium
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147
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Jeyaprakash AA, Geetha Rani P, Banuprakash Reddy G, Banumathi S, Betzel C, Sekar K, Surolia A, Vijayan M. Crystal structure of the jacalin-T-antigen complex and a comparative study of lectin-T-antigen complexes. J Mol Biol 2002; 321:637-45. [PMID: 12206779 DOI: 10.1016/s0022-2836(02)00674-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Thomsen-Friedenreich antigen (Galbeta1-3GalNAc), generally known as T-antigen, is expressed in more than 85% of human carcinomas. Therefore, proteins which specifically bind T-antigen have potential diagnostic value. Jacalin, a lectin from jack fruit (Artocarpus integrifolia) seeds, is a tetramer of molecular mass 66kDa. It is one of the very few proteins which are known to bind T-antigen. The crystal structure of the jacalin-T-antigen complex has been determined at 1.62A resolution. The interactions of the disaccharide at the binding site are predominantly through the GalNAc moiety, with Gal interacting only through water molecules. They include a hydrogen bond between the anomeric oxygen of GalNAc and the pi electrons of an aromatic side-chain. Several intermolecular interactions involving the bound carbohydrate contribute to the stability of the crystal structure. The present structure, along with that of the Me-alpha-Gal complex, provides a reasonable qualitative explanation for the known affinities of jacalin to different carbohydrate ligands and a plausible model of the binding of the lectin to T-antigen O-linked to seryl or threonyl residues. Including the present one, the structures of five lectin-T-antigen complexes are available. GalNAc occupies the primary binding site in three of them, while Gal occupies the site in two. The choice appears to be related to the ability of the lectin to bind sialylated sugars. In either case, most of the lectin-disaccharide interactions are at the primary binding site. The conformation of T-antigen in the five complexes is nearly the same.
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Affiliation(s)
- A Arockia Jeyaprakash
- Molecular Biophysics Unit, Indian Institute of Science, UGC Centre of Advanced Science, Bangalore, India
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148
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Bourne Y, Astoul CH, Zamboni V, Peumans WJ, Menu-Bouaouiche L, Van Damme EJM, Barre A, Rougé P. Structural basis for the unusual carbohydrate-binding specificity of jacalin towards galactose and mannose. Biochem J 2002; 364:173-80. [PMID: 11988090 PMCID: PMC1222559 DOI: 10.1042/bj3640173] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Evidence is presented that the specificity of jacalin, the seed lectin from jack fruit (Artocarpus integrifolia), is not directed exclusively against the T-antigen disaccharide Galbeta1,3GalNAc, lactose and galactose, but also against mannose and oligomannosides. Biochemical analyses based on surface-plasmon-resonance measurements, combined with the X-ray-crystallographic determination of the structure of a jacalin-alpha-methyl-mannose complex at 2 A resolution, demonstrated clearly that jacalin is fully capable of binding mannose. Besides mannose, jacalin also interacts readily with glucose, N-acetylneuraminic acid and N-acetylmuramic acid. Structural analyses demonstrated that the relatively large size of the carbohydrate-binding site enables jacalin to accommodate monosaccharides with different hydroxyl conformations and provided unambiguous evidence that the beta-prism structure of jacalin is a sufficiently flexible structural scaffold to confer different carbohydrate-binding specificities to a single lectin.
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Affiliation(s)
- Yves Bourne
- AFMB, UMR-CNRS 6098, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
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149
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Pratap JV, Jeyaprakash AA, Rani PG, Sekar K, Surolia A, Vijayan M. Crystal structures of artocarpin, a Moraceae lectin with mannose specificity, and its complex with methyl-alpha-D-mannose: implications to the generation of carbohydrate specificity. J Mol Biol 2002; 317:237-47. [PMID: 11902840 DOI: 10.1006/jmbi.2001.5432] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The seeds of jack fruit (Artocarpus integrifolia) contain two tetrameric lectins, jacalin and artocarpin. Jacalin was the first lectin found to exhibit the beta-prism I fold, which is characteristic of the Moraceae plant lectin family. Jacalin contains two polypeptide chains produced by a post-translational proteolysis which has been shown to be crucial for generating its specificity for galactose. Artocarpin is a single chain protein with considerable sequence similarity with jacalin. It, however, exhibits many properties different from those of jacalin. In particular, it is specific to mannose. The structures of two crystal forms, form I and form II, of the native lectin have been determined at 2.4 and 2.5 A resolution, respectively. The structure of the lectin complexed with methyl-alpha-mannose, has also been determined at 2.9 A resolution. The structure is similar to jacalin, although differences exist in details. The crystal structures and detailed modelling studies indicate that the following differences between the carbohydrate binding sites of artocarpin and jacalin are responsible for the difference in the specificities of the two lectins. Firstly, artocarpin does not contain, unlike jacalin, an N terminus generated by post-translational proteolysis. Secondly, there is no aromatic residue in the binding site of artocarpin whereas there are four in that of jacalin. A comparison with similar lectins of known structures or sequences, suggests that, in general, stacking interactions with aromatic residues are important for the binding of galactose while such interactions are usually absent in the carbohydrate binding sites of mannose-specific lectins with the beta-prism I fold.
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Affiliation(s)
- J V Pratap
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
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150
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Murphy AS, Hoogner KR, Peer WA, Taiz L. Identification, purification, and molecular cloning of N-1-naphthylphthalmic acid-binding plasma membrane-associated aminopeptidases from Arabidopsis. PLANT PHYSIOLOGY 2002; 128:935-50. [PMID: 11891249 PMCID: PMC152206 DOI: 10.1104/pp.010519] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Polar transport of the plant hormone auxin is regulated at the cellular level by inhibition of efflux from a plasma membrane (PM) carrier. Binding of the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA) to a regulatory site associated with the carrier has been characterized, but the NPA-binding protein(s) have not been identified. Experimental disparities between levels of high-affinity NPA binding and auxin transport inhibition can be explained by the presence of a low-affinity binding site and in vivo hydrolysis of NPA. In Arabidopsis, colocalization of NPA amidase and aminopeptidase (AP) activities, inhibition of auxin transport by artificial beta-naphthylamide substrates, and saturable displacement of NPA by the AP inhibitor bestatin suggest that PM APs may be involved in both low-affinity NPA binding and hydrolysis. We report the purification and molecular cloning of NPA-binding PM APs and associated proteins from Arabidopsis. This is the first report of PM APs in plants. PM proteins were purified by gel permeation, anion exchange, and NPA affinity chromatography monitored for tyrosine-AP activity. Lower affinity fractions contained two orthologs of mammalian APs involved in signal transduction and cell surface-extracellular matrix interactions. AtAPM1 and ATAPP1 have substrate specificities and inhibitor sensitivities similar to their mammalian orthologs, and have temporal and spatial expression patterns consistent with previous in planta histochemical data. Copurifying proteins suggest that the APs interact with secreted cell surface and cell wall proline-rich proteins. AtAPM1 and AtAPP1 are encoded by single genes. In vitro translation products of ATAPM1 and AtAPP1 have enzymatic activities similar to those of native proteins.
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Affiliation(s)
- Angus S Murphy
- Department of Horticulture and Landscape Architecture, Purdue University, West lafayette, Indiana 57907-1165, USA.
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