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Hashidzume A, Itami T, Kamon Y, Harada A. A Simplified Model for Multivalent Interaction Competing with a Low Molecular Weight Competitor. CHEM LETT 2020. [DOI: 10.1246/cl.200501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Akihito Hashidzume
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Takahiro Itami
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Yuri Kamon
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Akira Harada
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
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Thakur K, Kaur T, Kaur M, Hora R, Singh J. Exploration of carbohydrate binding behavior and anti-proliferative activities of Arisaema tortuosum lectin. BMC Mol Biol 2019; 20:15. [PMID: 31064325 PMCID: PMC6505227 DOI: 10.1186/s12867-019-0132-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 05/02/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Lectins have come a long way from being identified as proteins that agglutinate cells to promising therapeutic agents in modern medicine. Through their specific binding property, they have proven to be anti-cancer, anti-insect, anti-viral agents without affecting the non-target cells. The Arisaema tortuosum lectin (ATL) is a known anti-insect and anti-cancer candidate, also has interesting physical properties. In the present work, its carbohydrate binding behavior is investigated in detail, along with its anti-proliferative property. RESULTS The microcalorimetry of ATL with a complex glycoprotein asialofetuin demonstrated trivalency contributed by multiple binding sites and enthalpically driven spontaneous association. The complex sugar specificity of ATL towards multiple sugars was also demonstrated in glycan array analysis in which the trimannosyl pentasaccharide core N-glycan [Manα1-6(Manα1-3)Manβ1-4GlcNAcβ1-4GlcNAcβ] was the highest binding motif. The high binding glycans for ATL were high mannans, complex N-glycans, core fucosylated N-glycans and glycans with terminal lactosamine units attached to pentasaccharide core. ATL induced cell death in IMR-32 cells was observed as time dependent loss in cell number, formation of apoptotic bodies and DNA damage. As a first report of molecular cloning of ATL, the in silico analysis of its cDNA revealed ATL to be a β-sheet rich heterotetramer. A homology model of ATL showed beta prism architecture in each monomer with 85% residues in favoured region of Ramachandran plot. CONCLUSIONS Detailed exploration of carbohydrate binding behavior indicated ATL specificity towards complex glycans, while no binding to simple sugars, including mannose. Sequence analysis of ATL cDNA revealed that during the tandem evolutionary events, domain duplication and mutations lead to the loss of mannose specificity, acquiring of new sugar specificity towards complex sugars. It also resulted in the formation of a two-domain single chain polypeptide with both domains having different binding sites due to mutations within the consensus carbohydrate recognition sites [QXDXNXVXY]. This unique sugar specificity can account for its significant biological properties. Overall finding of present work signifies anti-cancer, anti-insect and anti-viral potential of ATL making it an interesting molecule for future research and/or theragnostic applications.
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Affiliation(s)
- Kshema Thakur
- Department of Molecular Biology & Biochemistry, Guru Nanak Dev University, Amritsar, Punjab 143005 India
- Present Address: Department of Biochemistry, Dr. Y.S.P. Govt. Medical College, Distt. Sirmaur, Nahan, H.P 173001 India
| | - Tarnjeet Kaur
- Department of Human Genetics, Guru Nanak Dev University, Amritsar, Punjab 143005 India
| | - Manpreet Kaur
- Department of Human Genetics, Guru Nanak Dev University, Amritsar, Punjab 143005 India
| | - Rachna Hora
- Department of Molecular Biology & Biochemistry, Guru Nanak Dev University, Amritsar, Punjab 143005 India
| | - Jatinder Singh
- Department of Molecular Biology & Biochemistry, Guru Nanak Dev University, Amritsar, Punjab 143005 India
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Chandran T, Sharma A, Vijayan M. Structural studies on a non-toxic homologue of type II RIPs from bitter gourd: Molecular basis of non-toxicity, conformational selection and glycan structure. J Biosci 2016; 40:929-41. [PMID: 26648038 DOI: 10.1007/s12038-015-9573-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The structures of nine independent crystals of bitter gourd seed lectin (BGSL), a non-toxic homologue of type II RIPs, and its sugar complexes have been determined. The four-chain, two-fold symmetric, protein is made up of two identical two-chain modules, each consisting of a catalytic chain and a lectin chain, connected by a disulphide bridge. The lectin chain is made up of two domains. Each domain carries a carbohydrate binding site in type II RIPs of known structure. BGSL has a sugar binding site only on one domain, thus impairing its interaction at the cell surface. The adenine binding site in the catalytic chain is defective. Thus, defects in sugar binding as well as adenine binding appear to contribute to the non-toxicity of the lectin. The plasticity of the molecule is mainly caused by the presence of two possible well defined conformations of a surface loop in the lectin chain. One of them is chosen in the sugar complexes, in a case of conformational selection, as the chosen conformation facilitates an additional interaction with the sugar, involving an arginyl residue in the loop. The N-glycosylation of the lectin involves a plant-specific glycan while that in toxic type II RIPs of known structure involves a glycan which is animal as well as plant specific.
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Abhinav KV, Vijayan M. Structural diversity and ligand specificity of lectins. The Bangalore effort. PURE APPL CHEM 2014. [DOI: 10.1515/pac-2014-0607] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractStructural studies in this laboratory encompass four of the five major classes of plant lectins, including the one discovered by us. In addition to addressing issues specific to individual lectins, the work provided insights into protein folding, quaternary association and generation of ligand specificity. Legume and β-prism fold lectins constitute families of proteins in which small alterations in essentially the same tertiary structure lead to large variations in quaternary structure, including that involving an open structure. Strategies for generating ligand specificity include water bridges, variation in loop length, post translational modification and oligomerization. Three of the structural classes investigated have subunits with three-fold symmetry. The symmetry in the structure is reflected in the sequence to different extents in different sub-classes. The evolutionary implications of this observation have been explored. The work on lectins has now been extended to those from mycobacteria.
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Affiliation(s)
| | - Mamannamana Vijayan
- 1Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560012, India
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Sharma A, Pohlentz G, Bobbili KB, Jeyaprakash AA, Chandran T, Mormann M, Swamy MJ, Vijayan M. The sequence and structure of snake gourd (Trichosanthes anguina) seed lectin, a three-chain nontoxic homologue of type II RIPs. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:1493-503. [PMID: 23897472 DOI: 10.1107/s0907444913010020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 04/11/2013] [Indexed: 11/10/2022]
Abstract
The sequence and structure of snake gourd seed lectin (SGSL), a nontoxic homologue of type II ribosome-inactivating proteins (RIPs), have been determined by mass spectrometry and X-ray crystallography, respectively. As in type II RIPs, the molecule consists of a lectin chain made up of two β-trefoil domains. The catalytic chain, which is connected through a disulfide bridge to the lectin chain in type II RIPs, is cleaved into two in SGSL. However, the integrity of the three-dimensional structure of the catalytic component of the molecule is preserved. This is the first time that a three-chain RIP or RIP homologue has been observed. A thorough examination of the sequence and structure of the protein and of its interactions with the bound methyl-α-galactose indicate that the nontoxicity of SGSL results from a combination of changes in the catalytic and the carbohydrate-binding sites. Detailed analyses of the sequences of type II RIPs of known structure and their homologues with unknown structure provide valuable insights into the evolution of this class of proteins. They also indicate some variability in carbohydrate-binding sites, which appears to contribute to the different levels of toxicity exhibited by lectins from various sources.
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Affiliation(s)
- Alok Sharma
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, Karnataka, India
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Abhinav KV, Sharma A, Vijayan M. Identification of mycobacterial lectins from genomic data. Proteins 2012. [DOI: 10.1002/prot.24219] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Upadhyay SK, Singh PK. Receptors of Garlic (Allium sativum) Lectins and Their Role in Insecticidal Action. Protein J 2012; 31:439-46. [DOI: 10.1007/s10930-012-9423-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Metabolic labeling enables selective photocrosslinking of O-GlcNAc-modified proteins to their binding partners. Proc Natl Acad Sci U S A 2012; 109:4834-9. [PMID: 22411826 DOI: 10.1073/pnas.1114356109] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
O-linked β-N-acetylglucosamine (O-GlcNAc) is a reversible posttranslational modification found on hundreds of nuclear and cytoplasmic proteins in higher eukaryotes. Despite its ubiquity and essentiality in mammals, functional roles for the O-GlcNAc modification remain poorly defined. Here we develop a combined genetic and chemical approach that enables introduction of the diazirine photocrosslinker onto the O-GlcNAc modification in cells. We engineered mammalian cells to produce diazirine-modified O-GlcNAc by expressing a mutant form of UDP-GlcNAc pyrophosphorylase and subsequently culturing these cells with a cell-permeable, diazirine-modified form of GlcNAc-1-phosphate. Irradiation of cells with UV light activated the crosslinker, resulting in formation of covalent bonds between O-GlcNAc-modified proteins and neighboring molecules, which could be identified by mass spectrometry. We used this method to identify interaction partners for the O-GlcNAc-modified FG-repeat nucleoporins. We observed crosslinking between FG-repeat nucleoporins and nuclear transport factors, suggesting that O-GlcNAc residues are intimately associated with essential recognition events in nuclear transport. Further, we propose that the method reported here could find widespread use in investigating the functional consequences of O-GlcNAcylation.
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Patra D, Sharma A, Chandran D, Vijayan M. Cloning, expression, purification, crystallization and preliminary X-ray studies of the mannose-binding lectin domain of MSMEG_3662 from Mycobacterium smegmatis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:596-9. [PMID: 21543870 PMCID: PMC3087649 DOI: 10.1107/s1744309111009547] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Accepted: 03/13/2011] [Indexed: 11/10/2022]
Abstract
The mannose-binding lectin domain of MSMEG_3662 from Mycobacterium smegmatis has been cloned, expressed, purified and crystallized and the crystals have been characterized using X-ray diffraction. The Matthews coefficient suggests the possibility of two lectin domains in the triclinic cell. The amino-acid sequence of the domain indicates structural similarity to well characterized β-prism II fold lectins.
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Affiliation(s)
- Dhabaleswar Patra
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Alok Sharma
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Divya Chandran
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Mamannamana Vijayan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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Moulaei T, Shenoy SR, Giomarelli B, Thomas C, McMahon JB, Dauter Z, O'Keefe BR, Wlodawer A. Monomerization of viral entry inhibitor griffithsin elucidates the relationship between multivalent binding to carbohydrates and anti-HIV activity. Structure 2011; 18:1104-15. [PMID: 20826337 PMCID: PMC3399781 DOI: 10.1016/j.str.2010.05.016] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 04/22/2010] [Accepted: 05/19/2010] [Indexed: 01/28/2023]
Abstract
Mutations were introduced to the domain-swapped homodimer of the antiviral lectin griffithsin (GRFT). Whereas several single and double mutants remained dimeric, insertion of either two or four amino acids at the dimerization interface resulted in a monomeric form of the protein (mGRFT). Monomeric character of the modified proteins was confirmed by sedimentation equilibrium ultracentrifugation and by their high resolution X-ray crystal structures, whereas their binding to carbohydrates was assessed by isothermal titration calorimetry. Cell-based antiviral activity assays utilizing different variants of mGRFT indicated that the monomeric form of the lectin had greatly reduced activity against HIV-1, suggesting that the antiviral activity of GRFT stems from crosslinking and aggregation of viral particles via multivalent interactions between GRFT and oligosaccharides present on HIV envelope glycoproteins. Atomic resolution crystal structure of a complex between mGRFT and nonamannoside revealed that a single mGRFT molecule binds to two different nonamannoside molecules through all three carbohydrate-binding sites present on the monomer.
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Affiliation(s)
- Tinoush Moulaei
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute-Frederick, Frederick, MD 21702-1201, USA
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Mazumder P, Mukhopadhyay C. Molecular modeling and NMR studies of benzyl substituted mannosyl trisaccharide binding to two mannose-specific lectins: Allium sativam agglutinin I and Concanavalin A. Biopolymers 2010; 93:952-67. [PMID: 20564057 DOI: 10.1002/bip.21503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The interaction of trimannoside, α-benzyl 3, 6-di-O-(α-D-mannopyranosyl)-α-D-mannopyranoside, 1 with ASAI (Allium sativam agglutinin I, garlic lectin) was studied to reveal the conformational preferences of this ligand in bound-state and detailed binding mode at atomic level. The binding phenomenon was then compared with another well-known mannose-binding lectin, ConA (Concanavalin A). Structural studies of the ligand in free state were done using NMR spectroscopy and Molecular Dynamics simulations. It is found that the substituted-trimannoside can undergo conformational transitions in solution, with one major and one minor conformation per glycosidic linkage (α 1→3 and α 1→6). On the other hand in the bound-state only one of the two major conformations was significantly populated. The role of phenyl ring in the binding process was explored. An extended binding site was observed for the trimannoside in ASAI utilizing the aromatic substituent, which is not seen in ConA. Binding data from difference absorption spectroscopy supported this fact that the binding of benzyl-substituted ligand is tighter with ASAI than ConA. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 952-967, 2010.
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Affiliation(s)
- Parichita Mazumder
- Department of Chemistry, University of Calcutta, 92, A.P.C. Road, Kolkata 700 009, India
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12
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Pavan GM, Danani A, Pricl S, Smith DK. Modeling the Multivalent Recognition between Dendritic Molecules and DNA: Understanding How Ligand “Sacrifice” and Screening Can Enhance Binding. J Am Chem Soc 2009; 131:9686-94. [DOI: 10.1021/ja901174k] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Giovanni M. Pavan
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Chemical Engineering (DICAMP), University of Trieste, Piazzale Europa 1, 34127 Trieste, Italy, Institute of Computer Integrated Manufacturing for Sustainable Innovation (ICIMSI), University for Applied Sciences of Southern Switzerland (SUPSI), Centro Galleria 2, Manno, CH-6928, Switzerland, and Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
| | - Andrea Danani
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Chemical Engineering (DICAMP), University of Trieste, Piazzale Europa 1, 34127 Trieste, Italy, Institute of Computer Integrated Manufacturing for Sustainable Innovation (ICIMSI), University for Applied Sciences of Southern Switzerland (SUPSI), Centro Galleria 2, Manno, CH-6928, Switzerland, and Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
| | - Sabrina Pricl
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Chemical Engineering (DICAMP), University of Trieste, Piazzale Europa 1, 34127 Trieste, Italy, Institute of Computer Integrated Manufacturing for Sustainable Innovation (ICIMSI), University for Applied Sciences of Southern Switzerland (SUPSI), Centro Galleria 2, Manno, CH-6928, Switzerland, and Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
| | - David K. Smith
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Chemical Engineering (DICAMP), University of Trieste, Piazzale Europa 1, 34127 Trieste, Italy, Institute of Computer Integrated Manufacturing for Sustainable Innovation (ICIMSI), University for Applied Sciences of Southern Switzerland (SUPSI), Centro Galleria 2, Manno, CH-6928, Switzerland, and Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
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Silva FP, Alexandre GMC, Ramos CHI, De-Simone SG. On the quaternary structure of a C-type lectin from Bothrops jararacussu venom--BJ-32 (BjcuL). Toxicon 2008; 52:944-53. [PMID: 18948130 DOI: 10.1016/j.toxicon.2008.10.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 09/24/2008] [Accepted: 10/07/2008] [Indexed: 10/21/2022]
Abstract
BJ-32 (also known as BjcuL) is a C-type lectin from the venom of Bothrops jararacussu with specificity for beta-galactosides and a remarkable ability to agglutinate several species of trypanosomatids. Our objective was to study the oligomerization state of native BJ-32 by using different biophysical and computational methods. Small-angle X-ray light scattering (SAXS) experiments disclosed a compact, globular protein with a radius of gyration of 36.72+/-0.04A and molecular weight calculated as 147.5+/-2.0kDa. From analytical ultracentrifugation analysis, it was determined that the BJ-32 sedimentation profile fits nicely to a decamer model. The analysis of the intrinsic emitted fluorescence spectra for BJ-32 solutions indicated that association of subunits in the decamer is accompanied by changes in the environment of Tryptophan residues. Both ab initio and comparative models of BJ-32 supported the resemblance of the decamer in the crystallographic structure from a close homologue, the rattlesnake venom lectin (RSL) from Crotalus atrox.
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Affiliation(s)
- F P Silva
- Laboratório de Bioquímica de Proteínas e Peptídeos, Instituto Oswaldo Cruz, Fiocruz, Av Brasil 4365, 21040-900 Rio de Janeiro, RJ, Brazil
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Cmoch P, Pakulski Z, Swaczynová J, Strnad M. Synthesis of lupane-type saponins bearing mannosyl and 3,6-branched trimannosyl residues and their evaluation as anticancer agents. Carbohydr Res 2008; 343:995-1003. [DOI: 10.1016/j.carres.2008.02.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Revised: 02/11/2008] [Accepted: 02/12/2008] [Indexed: 10/22/2022]
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Affiliation(s)
- M Vijayan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
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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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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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Shimon LJW, Rabinkov A, Shin I, Miron T, Mirelman D, Wilchek M, Frolow F. Two structures of alliinase from Alliium sativum L.: apo form and ternary complex with aminoacrylate reaction intermediate covalently bound to the PLP cofactor. J Mol Biol 2006; 366:611-25. [PMID: 17174334 DOI: 10.1016/j.jmb.2006.11.041] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Revised: 11/05/2006] [Accepted: 11/09/2006] [Indexed: 11/17/2022]
Abstract
Alliinase (alliin lyase EC 4.4.1.4), a PLP-dependent alpha, beta-eliminating lyase, constitutes one of the major protein components of garlic (Alliium sativum L.) bulbs. The enzyme is a homodimeric glycoprotein and catalyzes the conversion of a specific non-protein sulfur-containing amino acid alliin ((+S)-allyl-L-cysteine sulfoxide) to allicin (diallyl thiosulfinate, the well known biologically active component of freshly crushed garlic), pyruvate and ammonia. The enzyme was crystallized in the presence of (+S)-allyl-L-cysteine, forming dendrite-like monoclinic crystals. In addition, intentionally produced apo-enzyme was crystallized in tetragonal form. These structures of alliinase with associated glycans were resolved to 1.4 A and 1.61 A by molecular replacement. Branched hexasaccharide chains N-linked to Asn146 and trisaccharide chains N-linked to Asn328 are seen. The structure of hexasaccharide was found similar to "short chain complex vacuole type" oligosaccharide most commonly seen in plant glycoproteins. An unexpected state of the enzyme active site has been observed in the present structure. The electron density in the region of the cofactor made it possible to identify the cofactor moiety as aminoacrylate intermediate covalently bound to the PLP cofactor. It was found in the present structure to be stabilized by large number of interactions with surrounding protein residues. Moreover, the existence of the expected internal aldimine bond between the epsilon-amino group of Lys251 and the aldehyde of the PLP is ruled out on the basis of a distinct separation of electron density of Lys251. The structure of the active site cavity in the apo-form is nearly identical to that seen in the holo-form, with two sulfate ions, an acetate and several water molecules from crystallization conditions that replace and mimic the PLP cofactor.
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Affiliation(s)
- Linda J W Shimon
- Department of Chemical Research Support, The Weizmann Institute of Science, Rehovot 76100, Israel
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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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Ueda H, Fukushima H, Hatanaka Y, Ogawa H. Solubility-insolubility interconversion of sophoragrin, a mannose/glucose-specific lectin in Sophora japonica (Japanese pagoda tree) bark, regulated by the sugar-specific interaction. Biochem J 2005; 382:821-9. [PMID: 15222880 PMCID: PMC1133957 DOI: 10.1042/bj20040584] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2004] [Revised: 06/24/2004] [Accepted: 06/28/2004] [Indexed: 01/29/2023]
Abstract
Sophoragrin, a mannose/glucose-specific lectin in Sophora japonica (Japanese pagoda tree) bark, was the first lectin found to show self-aggregation that is dependent on the sugar concentration accompanying the interconversion between solubility and insolubility [Ueno, Ogawa, Matsumoto and Seno (1991) J. Biol. Chem. 266, 3146-3153]. The interconversion is regulated by the concentrations of Ca(2+) and specific sugars: mannose, glucose or sucrose. The specific glycotopes for sophoragrin were found in the sophoragrin subunit and an endogenous galactose-specific lectin, B-SJA-I (bark S. japonica agglutinin I), and the lectin subunit that binds to the glycotope was identified by photoaffinity glycan probes. Remarkably, the insoluble polymer of sophoragrin is dissociated by interaction with B-SJA-I into various soluble complexes. Based on these results, self-aggregation of sophoragrin was shown to be a unique homopolymerization due to the sugar-specific interaction. An immunostaining study indicated that sophoragrin localizes mainly in vacuoles of parenchymal cells coincidently with B-SJA-I. These results indicate that sophoragrin can sequester endogenous glycoprotein ligands via sugar-specific interactions, thus providing new insights into the occurrence and significance of the intravacuolar interaction shown by a legume lectin.
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Affiliation(s)
- Haruko Ueda
- *Department of Advanced Biosciences, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Hisako Fukushima
- *Department of Advanced Biosciences, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Yasumaru Hatanaka
- †Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani 2630, Toyama, 930-0194, Japan
| | - Haruko Ogawa
- *Department of Advanced Biosciences, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
- To whom correspondence should be addressed (email )
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