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Thompson AJ, Wu NC, Canales A, Kikuchi C, Zhu X, de Toro BF, Cañada FJ, Worth C, Wang S, McBride R, Peng W, Nycholat CM, Jiménez-Barbero J, Wilson IA, Paulson JC. Evolution of human H3N2 influenza virus receptor specificity has substantially expanded the receptor-binding domain site. Cell Host Microbe 2024; 32:261-275.e4. [PMID: 38307019 PMCID: PMC11057904 DOI: 10.1016/j.chom.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 11/14/2023] [Accepted: 01/09/2024] [Indexed: 02/04/2024]
Abstract
Hemagglutinins (HAs) from human influenza viruses descend from avian progenitors that bind α2-3-linked sialosides and must adapt to glycans with α2-6-linked sialic acids on human airway cells to transmit within the human population. Since their introduction during the 1968 pandemic, H3N2 viruses have evolved over the past five decades to preferentially recognize human α2-6-sialoside receptors that are elongated through addition of poly-LacNAc. We show that more recent H3N2 viruses now make increasingly complex interactions with elongated receptors while continuously selecting for strains maintaining this phenotype. This change in receptor engagement is accompanied by an extension of the traditional receptor-binding site to include residues in key antigenic sites on the surface of HA trimers. These results help explain the propensity for selection of antigenic variants, leading to vaccine mismatching, when H3N2 viruses are propagated in chicken eggs or cells that do not contain such receptors.
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Affiliation(s)
- Andrew J Thompson
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Nicholas C Wu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Angeles Canales
- Department of Organic Chemistry, Faculty of Chemistry, Universidad Complutense de Madrid, Avd. Complutense s/n, 28040 Madrid, Spain
| | - Chika Kikuchi
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Xueyong Zhu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Beatriz Fernández de Toro
- Structural and Chemical Biology Department, Centro de Investigaciones Biológicas Margarita Salas, C/Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Francisco J Cañada
- Structural and Chemical Biology Department, Centro de Investigaciones Biológicas Margarita Salas, C/Ramiro de Maeztu 9, 28040 Madrid, Spain; CIBERES, ISCIII, 28029 Madrid, Spain
| | - Charli Worth
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Shengyang Wang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ryan McBride
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Wenjie Peng
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Corwin M Nycholat
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jesús Jiménez-Barbero
- CIBERES, ISCIII, 28029 Madrid, Spain; CIC bioGUNE Bizkaia Science and Technology Park, 48160 Bilbao, Spain; IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Spain
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - James C Paulson
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA; Department of Immunology & Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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Martínez JD, Manzano AI, Calviño E, Diego AD, Rodriguez de Francisco B, Romanò C, Oscarson S, Millet O, Gabius HJ, Jiménez-Barbero J, Cañada FJ. Fluorinated Carbohydrates as Lectin Ligands: Simultaneous Screening of a Monosaccharide Library and Chemical Mapping by 19F NMR Spectroscopy. J Org Chem 2020; 85:16072-16081. [PMID: 33258593 PMCID: PMC7773211 DOI: 10.1021/acs.joc.0c01830] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Indexed: 02/06/2023]
Abstract
Molecular recognition of carbohydrates is a key step in essential biological processes. Carbohydrate receptors can distinguish monosaccharides even if they only differ in a single aspect of the orientation of the hydroxyl groups or harbor subtle chemical modifications. Hydroxyl-by-fluorine substitution has proven its merits for chemically mapping the importance of hydroxyl groups in carbohydrate-receptor interactions. 19F NMR spectroscopy could thus be adapted to allow contact mapping together with screening in compound mixtures. Using a library of fluorinated glucose (Glc), mannose (Man), and galactose (Gal) derived by systematically exchanging every hydroxyl group by a fluorine atom, we developed a strategy combining chemical mapping and 19F NMR T2 filtering-based screening. By testing this strategy on the proof-of-principle level with a library of 13 fluorinated monosaccharides to a set of three carbohydrate receptors of diverse origin, i.e. the human macrophage galactose-type lectin, a plant lectin, Pisum sativum agglutinin, and the bacterial Gal-/Glc-binding protein from Escherichia coli, it became possible to simultaneously define their monosaccharide selectivity and identify the essential hydroxyls for interaction.
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Affiliation(s)
- J. Daniel Martínez
- CIC
bioGUNE, Basque Research Technology Alliance, BRTA, Bizkaia Technology Park, Building 800, 48160 Derio, Spain
| | - Ana I. Manzano
- Centro
de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Eva Calviño
- Centro
de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Ana de Diego
- Centro
de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | | | - Cecilia Romanò
- Centre
for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Stefan Oscarson
- Centre
for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Oscar Millet
- CIC
bioGUNE, Basque Research Technology Alliance, BRTA, Bizkaia Technology Park, Building 800, 48160 Derio, Spain
| | - Hans-Joachim Gabius
- Institute
of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, 80539 Munich, Germany
| | - Jesús Jiménez-Barbero
- CIC
bioGUNE, Basque Research Technology Alliance, BRTA, Bizkaia Technology Park, Building 800, 48160 Derio, Spain
- Ikerbasque,
Basque Foundation for Science, 48009 Bilbao, Spain
- Department
of Organic Chemistry II, Faculty of Science and Technology, UPV-EHU, 48940 Leioa, Spain
| | - Francisco J. Cañada
- Centro
de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
- Centro
de Investigación Biomédica en Red-Enfermedades Respiratorias
(CIBERES), Avda Monforte
de Lemos 3-5, 28029 Madrid, Spain
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3
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Santana AG, Montalvillo-Jiménez L, Díaz-Casado L, Corzana F, Merino P, Cañada FJ, Jiménez-Osés G, Jiménez-Barbero J, Gómez AM, Asensio JL. Dissecting the Essential Role of Anomeric β-Triflates in Glycosylation Reactions. J Am Chem Soc 2020; 142:12501-12514. [DOI: 10.1021/jacs.0c05525] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
| | | | | | - Francisco Corzana
- Departamento Quı́mica and Centro de Investigación en Sı́ntesis Quı́mica, Universidad de La Rioja, 26006 Rioja, Spain
| | - Pedro Merino
- Instituto de Biocomputación y Fı́sica de Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018 Zaragoza, Spain
| | | | - Gonzalo Jiménez-Osés
- Center for Cooperative Research in Biosciences (CIC-bioGUNE), 48160 Derio, Spain
| | - Jesús Jiménez-Barbero
- Center for Cooperative Research in Biosciences (CIC-bioGUNE), 48160 Derio, Spain
- Ikerbasque Basque Foundation for Science, 48013 Bilbao, Basque
| | - Ana M. Gómez
- Instituto de Quı́mica Orgánica (IQOG-CSIC), 28006 Madrid, Spain
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Ayuso-Fernández I, De Lacey AL, Cañada FJ, Ruiz-Dueñas FJ, Martínez AT. Increase of Redox Potential during the Evolution of Enzymes Degrading Recalcitrant Lignin. Chemistry 2019; 25:2708-2712. [PMID: 30566756 PMCID: PMC6582443 DOI: 10.1002/chem.201805679] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Indexed: 11/09/2022]
Abstract
To investigate how ligninolytic peroxidases acquired the uniquely high redox potential they show today, their ancestors were resurrected and characterized. Unfortunately, the transient Compounds I (CI) and II (CII) from peroxide activation of the enzyme resting state (RS) are unstable. Therefore, the reduction potentials (E°') of the three redox couples (CI/RS, CI/CII and CII/RS) were estimated (for the first time in a ligninolytic peroxidase) from equilibrium concentrations analyzed by stopped-flow UV/Vis spectroscopy. Interestingly, the E°' of rate-limiting CII reduction to RS increased 70 mV from the common peroxidase ancestor to extant lignin peroxidase (LiP), and the same boost was observed for CI/RS and CI/CII, albeit with higher E°' values. A straightforward correlation was found between the E°' value and the progressive displacement of the proximal histidine Hϵ1 chemical shift in the NMR spectra, due to the higher paramagnetic effect of the heme Fe3+ . More interestingly, the E°' and NMR data also correlated with the evolutionary time, revealing that ancestral peroxidases increased their reduction potential in the evolution to LiP thanks to molecular rearrangements in their heme pocket during the last 400 million years.
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Affiliation(s)
- Iván Ayuso-Fernández
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040, Madrid, Spain
| | - Antonio L De Lacey
- Instituto de Catálisis y Petroleoquímica, CSIC, Marie Curie 2, E-28049, Madrid, Spain
| | - Francisco J Cañada
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040, Madrid, Spain
| | | | - Angel T Martínez
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040, Madrid, Spain
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5
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Antúnez-Mojica M, Rodríguez-Salarichs J, Redondo-Horcajo M, León A, Barasoain I, Canales Á, Cañada FJ, Jiménez-Barbero J, Alvarez L, Díaz JF. Structural and Biochemical Characterization of the Interaction of Tubulin with Potent Natural Analogues of Podophyllotoxin. J Nat Prod 2016; 79:2113-2121. [PMID: 27518758 DOI: 10.1021/acs.jnatprod.6b00428] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Four natural analogues of podophyllotoxin obtained from the Mexican medicinal plant Bursera fagaroides, namely, acetyl podophyllotoxin (2), 5'-desmethoxy-β-peltatin A methyl ether (3), 7',8'-dehydro acetyl podophyllotoxin (4), and burseranin (5), have been characterized, and their interactions with tubulin have been investigated. Cytotoxic activity measurements, followed by immunofluorescence microscopy and flow cytometry studies, demonstrated that these compounds disrupt microtubule networks in cells and cause cell cycle arrest in the G2/M phase in the A549 cell line. A tubulin binding assay showed that compounds 1-4 were potent assembly inhibitors, displaying binding to the colchicine site with Kb values ranging from 11.75 to 185.0 × 10(5) M(-1). In contrast, burseranin (5) was not able to inhibit tubulin assembly. From the structural perspective, the ligand-binding epitopes of compounds 1-3 have been mapped using STD-NMR, showing that B and E rings are the major points for interaction with the protein. The obtained results indicate that the inhibition of tubulin assembly of this family of compounds is more effective when there are at least two methoxyl groups at the E ring, along with a trans configuration of the lactone ring in the aryltetralin lignan core.
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Affiliation(s)
- Mayra Antúnez-Mojica
- Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos , Cuernavaca, Morelos 62209, México
| | - Javier Rodríguez-Salarichs
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas , Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Mariano Redondo-Horcajo
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas , Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Alejandra León
- Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos , Cuernavaca, Morelos 62209, México
| | - Isabel Barasoain
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas , Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Ángeles Canales
- Departamento de Química Orgánica I, Facultad Ciencias Químicas, Universidad Complutense de Madrid , Avenida Complutense s/n, 28040 Madrid, Spain
| | - F J Cañada
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas , Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Jesús Jiménez-Barbero
- CIC bioGUNE Parque Tecnológico de Bizkaia, Edif. 801A-1°, 48160 Derio-Bizkaia, Spain, and Ikerbasque, Basque Foundation for Science , Maria Diaz de Haro 3, 48009 Bilbao, Spain
| | - Laura Alvarez
- Centro de Investigaciones Químicas-IICBA, Universidad Autónoma del Estado de Morelos , Cuernavaca, Morelos 62209, México
| | - J Fernando Díaz
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas , Ramiro de Maeztu 9, 28040 Madrid, Spain
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Fernández de Córdoba FJ, Rodríguez-Carvajal MA, Cañada FJ, Tejero-Mateo P, Gil-Serrano AM, Jiménez-Barbero J. Solution Conformation and Dynamics of the O-Antigen of the Major Lipopolysaccharide fromSinorhizobium frediiSMH12. European J Org Chem 2008. [DOI: 10.1002/ejoc.200800190] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hermida C, Corrales G, Cañada FJ, Aragón JJ, Fernández-Mayoralas A. Optimizing the enzymatic synthesis of β-d-galactopyranosyl-d-xyloses for their use in the evaluation of lactase activity in vivo. Bioorg Med Chem 2007; 15:4836-40. [PMID: 17512743 DOI: 10.1016/j.bmc.2007.04.067] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 04/17/2007] [Accepted: 04/27/2007] [Indexed: 10/23/2022]
Abstract
Disaccharides 2-O-, 3-O-, and 4-O-beta-D-galactopyranosyl-D-xyloses (2, 3, and 1, respectively) were obtained by beta-galactosidase-catalyzed reactions for their use in the evaluation of intestinal lactase activity in vivo. Their administration to suckling rats followed by determination of the derived D-xylose in the urine and measurement of lactase activity in intestinal homogenates showed 1 to be the most suitable disaccharide for a potential test of the deficiency of intestinal lactase. The synthesis of 1 was further studied by evaluating the effect of different variables on the yield and regioselectivity of the enzymatic galactosylation, and the purification process was optimized.
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Affiliation(s)
- Carmen Hermida
- Departamento de Química Orgánica Biológica, Instituto de Química Orgánica General, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
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Fernández-Alonso MDC, Asensio JL, Cañada FJ, Jiménez-Barbero J, Cuevas G. G2 and DFT rigorous description of the inversion process of oxane and thiane used as simple ring systems to model sugar components. Chemphyschem 2003; 4:754-7. [PMID: 12901308 DOI: 10.1002/cphc.200200547] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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9
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Alonso-Plaza JM, Canales MA, Jiménez M, Roldán JL, García-Herrero A, Iturrino L, Asensio JL, Cañada FJ, Romero A, Siebert HC, André S, Solís D, Gabius HJ, Jiménez-Barbero J. NMR investigations of protein-carbohydrate interactions: insights into the topology of the bound conformation of a lactose isomer and beta-galactosyl xyloses to mistletoe lectin and galectin-1. Biochim Biophys Acta 2001; 1568:225-36. [PMID: 11786229 DOI: 10.1016/s0304-4165(01)00224-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A hallmark of oligosaccharides is their often limited spatial flexibility, allowing them to access a distinct set of conformers in solution. Viewing each individual or even the complete ensemble of conformations as potential binding partner(s) for lectins in protein-carbohydrate interactions, it is pertinent to address the question on the characteristics of bound state conformation(s) in solution. Also, it is possible that entering the lectin's binding site distorts the low-energy topology of a glycosidic linkage. As a step to delineate the strategy of ligand selection for galactosides, a common physiological docking point, we have performed a NMR study on two non-homologous lectins showing identical monosaccharide specificity. Thus, the conformation of lactose analogues bound to bovine heart galectin-1 and to mistletoe lectin in solution has been determined by transferred nuclear Overhauser effect measurements. It is demonstrated that the lectins select the syn conformation of lactose and various structural analogues (Galbeta(1-->4)Xyl, Galbeta(1-->3)Xyl, Galbeta(1-->2)Xyl, and Galbeta(1-->3)Glc) from the ensemble of presented conformations. No evidence for conformational distortion was obtained. Docking of the analogues to the modeled binding sites furnishes explanations, in structural terms, for exclusive recognition of the syn conformer despite the non-homologous design of the binding sites.
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10
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Cernuda-Morollón E, Pineda-Molina E, Cañada FJ, Pérez-Sala D. 15-Deoxy-Delta 12,14-prostaglandin J2 inhibition of NF-kappaB-DNA binding through covalent modification of the p50 subunit. J Biol Chem 2001; 276:35530-6. [PMID: 11466314 DOI: 10.1074/jbc.m104518200] [Citation(s) in RCA: 262] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclopentenone prostaglandins display anti-inflammatory activities and interfere with the signaling pathway that leads to activation of transcription factor NF-kappaB. Here we explore the possibility that the NF-kappaB subunit p50 may be a target for the cyclopentenone 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)). This prostaglandin inhibited the DNA binding ability of recombinant p50 in a dose-dependent manner. The inhibition required the cyclopentenone moiety and could be prevented but not reverted by glutathione and dithiothreitol. Moreover, a p50 mutant with a C62S mutation was resistant to inhibition, indicating that the effect of 15d-PGJ(2) was probably due to its interaction with cysteine 62 in p50. The covalent modification of p50 by 15d-PGJ(2) was demonstrated by reverse-phase high pressure liquid chromatography and mass spectrometry analysis that showed an increase in retention time and in the molecular mass of 15d-PGJ(2)-treated p50, respectively. The interaction between p50 and 15d-PGJ(2) was relevant in intact cells. 15d-PGJ(2) effectively inhibited cytokine-elicited NF-kappaB activity in HeLa without reducing IkappaBalpha degradation or nuclear translocation of NF-kappaB subunits. 15d-PGJ(2) reduced NF-kappaB DNA binding activity in isolated nuclear extracts, suggesting a direct effect on NF-kappaB proteins. Finally, treatment of HeLa with biotinylated-15d-PGJ(2) resulted in the formation of a 15d-PGJ(2)-p50 adduct as demonstrated by neutravidin binding and immunoprecipitation. These results clearly show that p50 is a target for covalent modification by 15d-PGJ(2) that results in inhibition of DNA binding.
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Affiliation(s)
- E Cernuda-Morollón
- Departamento de Estructura y Función de Proteinas, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Cientificas (C.S.I.C.), Madrid, Spain
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12
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Arribas JC, Herrero AG, Martín-Lomas M, Cañada FJ, He S, Withers SG. Differential mechanism-based labeling and unequivocal activity assignment of the two active sites of intestinal lactase/phlorizin hydrolase. Eur J Biochem 2000; 267:6996-7005. [PMID: 11106409 DOI: 10.1046/j.1432-1327.2000.01784.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Milk lactose is hydrolysed to galactose and glucose in the small intestine of mammals by the lactase/phlorizin hydrolase complex (LPH; EC 3.2.1.108/62). The two enzymatic activities, lactase and phlorizin hydrolase, are located in the same polypeptide chain. According to sequence homology, mature LPH contains two different regions (III and IV), each of them homologous to family 1 glycosidases and each with a putative active site. There has been some discrepancy with regard to the assignment of enzymatic activity to the two active sites. Here we show differential reactivity of the two active sites with mechanism-based glycosidase inhibitors. When LPH is treated with 2',4'-dinitrophenyl 2-deoxy-2-fluoro-beta-D-glucopyranoside (1) and 2', 4'-dinitrophenyl-2-deoxy-2-fluoro-beta-D-galactopyranoside (2), known mechanism-based inhibitors of glycosidases, it is observed that compound 1 preferentially inactivates the phlorizin hydrolase activity whereas compound 2 is selective for the lactase active site. On the other hand, glycals (D-glucal and D-galactal) competitively inhibit lactase activity but not phlorizin hydrolase activity. This allows labeling of the phlorizin site with compound 1 by protection with a glycal. By differential labeling of each active site using 1 and 2 followed by proteolysis and MS analysis of the labeled fragments, we confirm that the phlorizin hydrolysis occurs mainly at the active site located at region III of LPH and that the active site located at region IV is responsible for the lactase activity. This assignment is coincident with that proposed from the results of recent active-site mutagenesis studies [Zecca, L., Mesonero, J.E., Stutz, A., Poiree, J.C., Giudicelli, J., Cursio, R., Gloor, S.M. & Semenza, G. (1998) FEBS Lett. 435, 225-228] and opposite to that based on data from early affinity labeling with conduritol B epoxide [Wacker, W., Keller, P., Falchetto, R., Legler, G. & Semenza, G. (1992) J. Biol. Chem. 267, 18744-18752].
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Affiliation(s)
- J C Arribas
- Departamento de Química Orgánica Biológica, Instituto de Química Orgánica General, C.S.I.C., Madrid, Spain
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Siebert HC, André S, Asensio JL, Cañada FJ, Dong X, Espinosa JF, Frank M, Gilleron M, Kaltner H, Kozár T, Bovin NV, von Der Lieth CW, Vliegenthart JF, Jiménez-Barbero J, Gabius HJ. A new combined computational and NMR-spectroscopical strategy for the identification of additional conformational constraints of the bound ligand in an aprotic solvent. Chembiochem 2000; 1:181-95. [PMID: 11828411 DOI: 10.1002/1439-7633(20001002)1:3<181::aid-cbic181>3.0.co;2-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This study documents the feasibility of switching to an aprotic medium in sugar receptor research. The solvent change offers additional insights into mechanistic details of receptor--carbohydrate ligand interactions. If a receptor retained binding capacity in an aprotic medium, solvent-exchangeable protons of the ligand would not undergo transfer and could act as additional sensors, thus improving the level of reliability in conformational analysis. To probe this possibility, we first focused on hevein, the smallest lectin found in nature. The NMR-spectroscopic measurements verified complexation, albeit with progressively reduced affinity by more than 1.5 orders of magnitude, in mixtures of up to 50% dimethyl sulfoxide (DMSO). Since hevein lacks the compact beta-strand arrangement of other sugar receptors, such a structural motif may confer enhanced resistance to solvent exchange. Two settings of solid-phase activity assays proved this assumption for three types of alpha- and/or beta-galactoside-binding proteins, that is, a human immunoglobulin G (IgG) subfraction, the mistletoe lectin, and a member of the galectin family of animal lectins. Computer-assisted calculations and NMR experiments also revealed no conspicuous impact of the solvent on the conformational properties of the tested ligands. To define all possible nuclear Overhauser effect (NOE) contacts in a certain conformation and to predict involvement of exchangeable protons, we established a new screening protocol applicable during a given molecular dynamics (MD) trajectory and calculated population densities of distinct contacts. Experimentally, transferred NOE (tr-NOE) experiments with IgG molecules and the disaccharide Gal'alpha1-3Galbeta1-R in DMSO as solvent disclosed that such an additional crosspeak, that is, Gal'OH2--GalOH4, was even detectable for the bound ligand under conditions in which spin diffusion effects are suppressed. Further measurements with the plant lectin and galectins confirmed line broadening of ligand signals and gave access to characteristic crosspeaks in the aprotic solvent and its mixtures with water. Our combined biochemical, computational, and NMR-spectroscopical strategy is expected to contribute notably to the precise elucidation of the geometry of ligands bound to compactly folded sugar receptors and of the role of water molecules in protein--ligand (carbohydrate) recognition, with relevance to areas beyond the glycosciences.
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Affiliation(s)
- H C Siebert
- Institut für Physiologische Chemie, Tierärztliche Fakultät Ludwig-Maximilians-Universität Veterinärstrasse 13, 80539 München Germany
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14
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Asensio JL, Siebert HC, von Der Lieth CW, Laynez J, Bruix M, Soedjanaamadja UM, Beintema JJ, Cañada FJ, Gabius HJ, Jiménez-Barbero J. NMR investigations of protein-carbohydrate interactions: studies on the relevance of Trp/Tyr variations in lectin binding sites as deduced from titration microcalorimetry and NMR studies on hevein domains. Determination of the NMR structure of the complex between pseudohevein and N,N',N"-triacetylchitotriose. Proteins 2000; 40:218-36. [PMID: 10842338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Model studies on lectins and their interactions with carbohydrate ligands in solution are essential to gain insights into the driving forces for complex formation and to optimize programs for computer simulations. The specific interaction of pseudohevein with N,N', N"-triacetylchitotriose has been analyzed by (1)H-NMR spectroscopy. Because of its small size, with a chain length of 45 amino acids, this lectin is a prime target to solution-structure determination by NOESY NMR experiments in water. The NMR-analysis was extended to assessment of the topology of the complex between pseudohevein and N, N',N"-triacetylchitotriose. NOESY experiments in water solution provided 342 protein proton-proton distance constraints. Binding of the ligand did not affect the pattern of the protein nuclear Overhauser effect signal noticeably, what would otherwise be indicative of a ligand-induced conformational change. The average backbone (residues 3-41) RMSD of the 20 refined structures was 1.14 A, whereas the heavy atom RMSD was 2.18 A. Two different orientations of the trisaccharide within the pseudohevein binding site are suggested, furnishing an explanation in structural terms for the lectin's capacity to target chitin. In both cases, hydrogen bonds and van der Waals contacts confer stability to the complexes. This conclusion is corroborated by the thermodynamic parameters of binding determined by NMR and isothermal titration calorimetry. The association process was enthalpically driven. In relation to hevein, the Trp/Tyr-substitution in the binding pocket has only a small effect on the free energy of binding in contrast to engineered galectin-1 and a mammalian C-type lectin. A comparison of the three-dimensional structure of pseudohevein in solution to those reported for wheat germ agglutinin (WGA) in the solid state and for hevein and WGA-B in solution has been performed, providing a data source about structural variability of the hevein domains. The experimentally derived structures and the values of the solvent accessibilities for several key residues have also been compared with conformations obtained by molecular dynamics simulations, pointing to the necessity to further refine the programs to enhance their predictive reliability and, thus, underscoring the importance of this kind of combined analysis in model systems.
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Affiliation(s)
- J L Asensio
- Instituto de Química Orgánica General, CSIC, Madrid, Spain
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15
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Espinosa JF, Asensio JL, García JL, Laynez J, Bruix M, Wright C, Siebert HC, Gabius HJ, Cañada FJ, Jiménez-Barbero J. NMR investigations of protein-carbohydrate interactions binding studies and refined three-dimensional solution structure of the complex between the B domain of wheat germ agglutinin and N,N', N"-triacetylchitotriose. Eur J Biochem 2000; 267:3965-78. [PMID: 10866795 DOI: 10.1046/j.1432-1327.2000.01415.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The specific interaction of the isolated B domain of wheat germ agglutinin (WGA-B) with N,N',N"-triacetylchitotriose has been analyzed by 1H-NMR spectroscopy. The association constants for the binding of WGA-B to this trisaccharide have been determined from both 1H-NMR titration experiments and microcalorimetry methods. Entropy and enthalpy of binding have been obtained. The driving force for the binding process is provided by a negative DeltaH which is partially compensated by negative DeltaS. These negative signs indicate that hydrogen bonding and van der Waals forces are the major interactions stabilizing the complex. NOESY NMR experiments in water solution provided 327 protein proton-proton distance constraints. All the experimental constraints were used in a refinement protocol including restrained molecular dynamics in order to determine the refined solution conformation of this protein/carbohydrate complex. With regard to the NMR structure of the free protein, no important changes in the protein NOEs were observed, indicating that carbohydrate-induced conformational changes are small. The average backbone rmsd of the 35 refined structures was 1.05 A, while the heavy atom rmsd was 2.10 A. Focusing on the bound ligand, two different orientations of the trisaccharide within WGA-B binding site are possible. It can be deduced that both hydrogen bonds and van der Waals contacts confer stability to both complexes. A comparison of the three-dimensional structure of WGA-B in solution to that reported in the solid state and to those deduced for hevein and pseudohevein in solution has also been performed.
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Affiliation(s)
- J F Espinosa
- Instituto de Química Orgánica General, Centro de Investigaciones Biológicas, Instituto de Química Física Rocasolano, and Instituto de Estructura de la Materia, CSIC, Madrid, Spain
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16
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Asensio JL, Cañada FJ, Siebert HC, Laynez J, Poveda A, Nieto PM, Soedjanaamadja UM, Gabius HJ, Jiménez-Barbero J. Structural basis for chitin recognition by defense proteins: GlcNAc residues are bound in a multivalent fashion by extended binding sites in hevein domains. Chem Biol 2000; 7:529-43. [PMID: 10903932 DOI: 10.1016/s1074-5521(00)00136-8] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Many plants respond to pathogenic attack by producing defense proteins that are capable of reversible binding to chitin, a polysaccharide present in the cell wall of fungi and the exoskeleton of insects. Most of these chitin-binding proteins include a common structural motif of 30 to 43 residues organized around a conserved four-disulfide core, known as the 'hevein domain' or 'chitin-binding' motif. Although a number of structural and thermodynamic studies on hevein-type domains have been reported, these studies do not clarify how chitin recognition is achieved. RESULTS The specific interaction of hevein with several (GlcNAc)(n) oligomers has been studied using nuclear magnetic resonance (NMR), analytical ultracentrifugation and isothermal titration microcalorimetry (ITC). The data demonstrate that hevein binds (GlcNAc)(2-4) in 1:1 stoichiometry with millimolar affinity. In contrast, for (GlcNAc)(5), a significant increase in binding affinity is observed. Analytical ultracentrifugation studies on the hevein-(GlcNAc)(5,8) interaction allowed detection of protein-carbohydrate complexes with a ratio of 2:1 in solution. NMR structural studies on the hevein-(GlcNAc)(5) complex showed the existence of an extended binding site with at least five GlcNAc units directly involved in protein-sugar contacts. CONCLUSIONS The first detailed structural model for the hevein-chitin complex is presented on the basis of the analysis of NMR data. The resulting model, in combination with ITC and analytical ultracentrifugation data, conclusively shows that recognition of chitin by hevein domains is a dynamic process, which is not exclusively restricted to the binding of the nonreducing end of the polymer as previously thought. This allows chitin to bind with high affinity to a variable number of protein molecules, depending on the polysaccharide chain length. The biological process is multivalent.
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Affiliation(s)
- J L Asensio
- CSIC, Instituto de Química Orgánica General, Madrid, Spain
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17
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Asensio JL, Cañada FJ, Cheng X, Khan N, Mootoo DR, Jiménez-Barbero J. Conformational differences between O- and C-glycosides: the alpha-O-man-(1-->1)-beta-Gal/alpha-C-Man-(1-->1)-beta-Gal case--a decisive demonstration of the importance of the exo-anomeric effect on the conformation of glycosides. Chemistry 2000; 6:1035-41. [PMID: 10785824 DOI: 10.1002/(sici)1521-3765(20000317)6:6<1035::aid-chem1035>3.0.co;2-g] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The conformational behavior of alpha-O-Man-(1-->1)-beta-Gal (1) and its C-analogue (2) has been studied using J/NOE NMR data, molecular mechanics, molecular dynamics, and ab initio calculations. The population distribution around the glycosidic linkages of 1 and 2 is rather different, especially for the alpha-Man linkage. A lower limit for the exo-anomeric effect in water has been experimentally determined.
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Affiliation(s)
- J L Asensio
- Departamento de Química Orgánica Biológica, CSIC, Madrid, Spain
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18
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Day AJ, Cañada FJ, Díaz JC, Kroon PA, Mclauchlan R, Faulds CB, Plumb GW, Morgan MR, Williamson G. Dietary flavonoid and isoflavone glycosides are hydrolysed by the lactase site of lactase phlorizin hydrolase. FEBS Lett 2000; 468:166-70. [PMID: 10692580 DOI: 10.1016/s0014-5793(00)01211-4] [Citation(s) in RCA: 508] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lactase phlorizin hydrolase (LPH; EC 3.2.1.62) is a membrane-bound, family 1 beta-glycosidase found on the brush border of the mammalian small intestine. LPH, purified from sheep small intestine, was capable of hydrolysing a range of flavonol and isoflavone glycosides. The catalytic efficiency (k(cat)/K(m)) for the hydrolysis of quercetin-4'-glucoside, quercetin-3-glucoside, genistein-7-glucoside and daidzein-7-glucoside was 170, 137, 77 and 14 (mM(-1) s(-1)) respectively. The majority of the activity occurred at the lactase and not phlorizin hydrolase site. The ability of LPH to deglycosylate dietary (iso)flavonoid glycosides suggests a possible role for this enzyme in the metabolism of these biologically active compounds.
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Affiliation(s)
- A J Day
- Diet, Health and Consumer Science Division, Institute of Food Research, Norwich Research Park, Colney, Norwich, UK.
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19
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Díaz Pérez VM, García Moreno MI, Ortiz Mellet C, Fuentes J, Díaz Arribas JC, Cañada FJ, García Fernández JM. Generalized anomeric effect in action: synthesis and evaluation of stable reducing indolizidine glycomimetics as glycosidase inhibitors. J Org Chem 2000; 65:136-43. [PMID: 10813907 DOI: 10.1021/jo991242o] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of aminoketalic castanospermine analogues incorporating a stereoelectronically anchored axial hydroxy group at the pseudoanomeric stereocenter (C-5) have been synthesized to satisfy the need for glucosidase inhibitors that are highly selective for alpha-glucosidases. The polyhydroxylated bicyclic system was built from readily available hexofuranose derivatives through a synthetic scheme that involved (i) the construction of a five-membered cyclic (thio)carbamate or (thio)urea moiety at the nonreducing end and (ii) the intramolecular nucleophilic addition of the heterocyclic thiocarbamic nitrogen atom to the masked aldehyde group of the monosaccharide. A biological screening of the resulting reducing 2-oxa- and 2-azaindolizidines against several glycosidase enzymes is reported.
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Affiliation(s)
- V M Díaz Pérez
- Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, E-41071, Sevilla, Spain
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20
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Abstract
Several areas of research in the study of the structure and dynamics of free and protein-bound carbohydrates have experienced considerable advances during the past year. These include the application of state-of-the-art NMR techniques using (13)C-labeled sugars to obtain conformational information, the full structural characterization of several saccharides that either form part of glycoproteins or form noncovalent complexes, both in solution and in the solid state, the description of several enzyme-carbohydrate complexes at the atomic level and last, but not least, the development and analysis of calculation protocols to predict the dynamical and conformational behavior of oligosaccharides.
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Affiliation(s)
- J Jiménez-Barbero
- Dept Química Orgánica Biológica, Instituto Química Orgánica, CSIC Juan de la Cierva 3, 28006, Madrid, Spain.
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21
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Asensio JL, Cañada FJ, Bruix M, González C, Khiar N, Rodríguez-Romero A, Jiménez-Barbero J. NMR investigations of protein-carbohydrate interactions: refined three-dimensional structure of the complex between hevein and methyl beta-chitobioside. Glycobiology 1998; 8:569-77. [PMID: 9592123 DOI: 10.1093/glycob/8.6.569] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The specific interaction of hevein with GlcNAc-containing oligosaccharides has been analyzed by1H-NMR spectroscopy. The association constants for the binding of hevein to a variety of ligands have been estimated from1H-NMR titration experiments. The association constants increase in the order GlcNAc-alpha(1-->6)-Man < GlcNAc < benzyl-beta-GlcNAc < p-nitrophenyl-beta-GlcNAc < chitobiose < p-nitrophenyl-beta-chitobioside < methyl-beta-chitobioside < chitotriose. Entropy and enthalpy of binding for different complexes have been obtained from van't Hoff analysis. The driving force for the binding process is provided by a negative DeltaH0which is partially compensated by negative DeltaS0. These negative signs indicate that hydrogen bonding and van der Waals forces are the major interactions stabilizing the complex. NOESY NMR experiments in water solution provided 475 accurate protein proton-proton distance constraints after employing the MARDIGRAS program. In addition, 15 unambiguous protein/carbohydrate NOEs were detected. All the experimental constraints were used in a refinement protocol including restrained molecular dynamics in order to determine the highly refined solution conformation of this protein-carbohydrate complex. With regard to the NMR structure of the free protein, no important changes in the protein nOe's were observed, indicating that carbohydrate-induced conformational changes are small. The average backbone rmsd of the 20 refined structures was 0.055 nm, while the heavy atom rmsd was 0.116 nm. It can be deduced that both hydrogen bonds and van der Waals contacts confer stability to the complex. A comparison of the three-dimensional structure of hevein in solution to those reported for wheat germ agglutinin (WGA) and hevein itself in the solid state has also been performed. The polypeptide conformation has also been compared to the NMR-derived structure of a smaller antifungical peptide, Ac-AMP2.
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Affiliation(s)
- J L Asensio
- Instituto de Química Orgánica General, CSIC, Madrid, Spain
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22
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Abstract
S-Farnesyl-thioacetic acid (FTA), a competitive inhibitor of isoprenylated protein methyltransferase, potently suppressed the growth of HL-60 cells and induced apoptosis, as evidenced by the development of increased annexin-V binding, decreased binding of DNA dyes and internucleosomal DNA degradation. FTA did not impair the membrane association of ras proteins, conversely, it brought about a decrease in the proportion of ras present in the cytosolic fraction. Farnesylated molecules which are weak inhibitors of the methyltransferase also induced DNA laddering and reduced the proportion of cytosolic ras. These findings suggest that neither inhibition of isoprenylated protein methylation nor impairment of ras membrane association are essential for apoptosis induced by farnesylcysteine analogs.
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Affiliation(s)
- D Pérez-Sala
- Departamento de Estructura y Función de Proteínas, Centro de Investigaciones Biológicas, C.S.I.C., Madrid, Spain.
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23
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Montero E, Vallmitjana M, Pérez-Pons JA, Querol E, Jiménez-Barbero J, Cañada FJ. NMR studies of the conformation of thiocellobiose bound to a beta-glucosidase from Streptomyces sp. FEBS Lett 1998; 421:243-8. [PMID: 9468315 DOI: 10.1016/s0014-5793(97)01571-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The conformation of 4-thiocellobiose bound to beta-glucosidase from Streptomyces sp. has been studied by 1H-NMR transferred nuclear Overhauser effect spectroscopy (TR-NOE). Thiocellobiose behaves as an inhibitor of this glucosidase when cellobiose is used as substrate. NOE measurements and molecular mechanics calculations have also been performed to estimate the probability distribution of conformers of thiocellobiose when free in solution. Experimental data show that, in contrast with the natural O-analogue, thiocellobiose presents three conformational families in the free state, namely syn, anti-psi and anti-phi, whilst only one of them (syn) is recognized by the enzyme.
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Affiliation(s)
- E Montero
- Instituto de Química Orgánica, CSIC, Madrid, Spain
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24
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Montero E, Alonso J, Cañada FJ, Fernández-Mayoralas A, Martín-Lomas M. Regioselectivity of the enzymatic transgalactosidation of D- and L-xylose catalysed by beta-galactosidases. Carbohydr Res 1997; 305:383-91. [PMID: 9648257 DOI: 10.1016/s0008-6215(97)10002-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The regioselectivity of enzymatic transgalactosidation depends on the source of the beta-galactosidase used. When the galactosyl acceptor only contains secondary hydroxyl groups, e.g., D- or L-xylose, it is possible to find an enzyme that catalyses preferentially the synthesis of any of the three regioisomers 4-, 3- and 2-O-beta-D-galactopyranosyl-D-xylose (1, 2 and 3, respectively) or 4-, 3- and 2-O-beta-D-galactopyranosyl-L-xylose (4, 5 and 6, respectively). Enriched mixtures in 1, 2 or 3 were obtained using beta-galactosidases from Escherichia coli, bovine testes or Aspergillus oryzae, respectively, by transgalactosidation reaction of O-nitrophenyl-beta-D-galactopyranoside and D-xylose, and enriched mixtures in 4, 5 or 6 were obtained in a similar way using beta-galactosidases from Aspergillus oryzae, lamb small-intestine (intestinal lactase-phloridzin hydrolase) or Saccharomyces fragilis, respectively, using L-xylose as acceptor.
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Affiliation(s)
- E Montero
- Instituto de Química Orgánica, CSIC, Madrid, Spain
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25
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L. Jiménez Blanco J, M. Díaz Pérez V, Ortiz Mellet C, Fuentes J, M. García Fernández J, C. Díaz Arribas J, J. Cañada F. N-Thiocarbonyl azasugars: a new family of carbohydrate mimics with controlled anomeric configuration. Chem Commun (Camb) 1997. [DOI: 10.1039/a705755e] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Aragón JJ, Cañada FJ, Fernández-Mayoralas A, López R, Martín-Lomas M, Villanueva D. A direct enzymatic synthesis of beta-D-galactopyranosyl-D-xylopyranosides and their use to evaluate rat intestinal lactase activity in vivo. Carbohydr Res 1996; 290:209-16. [PMID: 8823908 DOI: 10.1016/0008-6215(96)00113-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
By enzymatic beta-D-galactosylation of D-xylose a mixture of 4-, 3-, and 2-O-beta-D-galactopyranosyl-D-xyloses (1, 4, and 7, respectively) was obtained in 50% isolated yield. Disaccharides 1, 4, and 7 are substrates of intestinal lactase isolated from lamb small intestine with K(m) values of 250.0, 4.5, and 14.0 mM, respectively. The mixture was used to monitor the normal decline in lactase activity in rats that takes place after weaning. The data obtained by this method correlated with the levels of intestinal lactase activity in the same animals after being sacrificed.
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Affiliation(s)
- J J Aragón
- Instituto de Química Orgánica, CSIC, Madrid, Spain
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27
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Saura M, Pérez-Sala D, Cañada FJ, Lamas S. Role of tetrahydrobiopterin availability in the regulation of nitric-oxide synthase expression in human mesangial cells. J Biol Chem 1996; 271:14290-5. [PMID: 8662883 DOI: 10.1074/jbc.271.24.14290] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Human mesangial cells express an inducible form of nitric-oxide synthase (iNOS) after treatment with cytokines. Tetrahydrobiopterin (BH4), an essential cofactor for NOS, is required for cytokine-induced NO generation. We report here that BH4 is necessary not only for the activity but also for the expression of iNOS in human mesangial cells. Inhibition of de novo BH4 synthesis with 2,4-diamino-6-hydroxypyrimidine (DAHP) significantly attenuated iNOS activity as well as mRNA and protein expression in response to interleukin 1beta plus tumor necrosis factor alpha (IL-1beta/TNF-alpha). In contrast, sepiapterin, which provides BH4 through the pterin salvage pathway, strongly potentiated IL-1beta/TNF-alpha-induced iNOS expression and abrogated the inhibitory effect of DAHP. Inhibition of the pterin salvage pathway with methotrexate abolished sepiapterin potentiation of iNOS induction but did not alter the effect of IL-1beta/TNF-alpha. Determination of intracellular pteridines confirmed that sepiapterin markedly raised BH4 content, an effect that was blocked by methotrexate. These results suggest that BH4 availability plays an important role in the regulation of iNOS expression. The effect of BH4 appears to be mediated, at least in part, by an increase in mRNA stability, as indicated by the observation that DAHP shortened, whereas sepiapterin prolonged the half-life of IL-1beta/TNF-alpha-induced iNOS mRNA. Taken together, our results suggest that the biosynthesis of BH4 contributes to cytokine induction of iNOS expression in human mesangial cells through the stabilization of iNOS mRNA.
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Affiliation(s)
- M Saura
- Centro de Investigaciones Biológicas and the Instituto de Química Orgánica General, Consejo Superior de Investigaciones Científicas, Madrid 28006, Spain
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28
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Asensio JL, Cañada FJ, Jimenez-Barbero J. Studies of the bound conformations of methyl alpha-lactoside and methyl beta-allolactoside to ricin B chain using transferred NOE experiments in the laboratory and rotating frames, assisted by molecular mechanics and dynamics calculations. Eur J Biochem 1995; 233:618-30. [PMID: 7588809 DOI: 10.1111/j.1432-1033.1995.618_2.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The conformation in solution of methyl beta-galactopyranosyl-(1-->4)-alpha-glucopyranoside (methyl alpha-lactoside) and methyl beta-galactopyranosyl-(1-->6)-beta-glucopyranoside (methyl beta-allolactoside) has been studied through NMR spectroscopy and molecular mechanics calculations. NOE measurements both in the laboratory and rotating frames, have been interpreted in terms of an ensemble average distribution of conformers. Molecular mechanics calculations have been performed to estimate the probability distribution of conformers from the steric energy maps. The experimental results indicate that methyl alpha-lactoside spends about 90% of its time in a broad low-energy region close to the global minimum, while methyl beta-allolactoside presents much higher flexibility. The conformational changes that occur when both disaccharides are bound to the ricin B chain in aqueous solution have been studied using transferred NOE experiments at several protein/ligand ratios. The observed data indicate that the protein causes a conformational variation in the torsion angles of methyl alpha-lactoside changing towards smaller angle values (phi/psi approximately -20/-20), although the recognized conformer is still within the lowest energy region. In particular, the torsional changes separate Gal H1 from Glc H3 and Glc H6 protons, with a noticeable decrease in the intensities of the corresponding NOE cross-peaks, which were clearly observed for the free disaccharide. On the other hand, different conformations around the phi, psi, and omega glycosidic bonds of methyl beta-allolactoside are recognized by the lectin. In fact, for the methyl-beta-allolactoside-ricin-B complex, only the NOESY cross-peaks corresponding to the protons of the galactose residue are negative, as expected for a molecule in the slow motion regime. In contrast, the corresponding cross peaks for the glucose residue were about zero, as expected for a molecule whose motion is practically independent of the protein. However, for the methyl-alpha-lactoside-ricin-B complex, all the NOESY cross-peaks for both the galactose and glucose moieties were clearly negative. From the NMR experimental point of view, it is demonstrated that the comparison of longitudinal and transversal transferred NOEs allows one to clearly differentiate direct enhancements from spin diffusion effects, which are of major concern when analysing NOE spectra of macromolecules.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J L Asensio
- Departamento de Química Orgánica Biológica, Instituto de Química Orgánica, Madrid, Spain
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29
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Fernandez P, Cañada FJ, Jiménez-Barbero J, Martín-Lomas M. Substrate specificity of small-intestinal lactase: study of the steric effects and hydrogen bonds involved in enzyme-substrate interaction. Carbohydr Res 1995; 271:31-42. [PMID: 7648581 DOI: 10.1016/0008-6215(95)00034-q] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Milk lactose is hydrolysed to D-galactose and D-glucose in the small intestine of mammals by the lactase-phlorizin hydrolase complex (LPH, EC 3.2.1.23-62). Lactase activity has broad substrate selectivity and several glycosides are substrates. Recently, using the monodeoxy derivatives of methyl beta-lactoside (1), we have shown the importance of each hydroxyl group in the substrate molecule concerning the interaction with the enzyme. Now we have studied the corresponding O-methyl derivatives, as well as some of the halo derivatives of 1. We have found that the enzyme presents steric restrictions to the recognition of substrates modified in the galactose moiety. In contrast, the binding site for the aglycon part of the substrate is looser. On the other hand, we have previously shown that HO-3' and HO-6 were important for the recognition of the substrate by the enzyme. Now we have found that the corresponding fluorine derivatives are not, or very poorly, recognized. This suggests that the HO-3' and HO-6 participate, as donors, in hydrogen bonds in the interaction with the enzyme.
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Affiliation(s)
- P Fernandez
- Instituto de Química Orgánica, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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Rivera-Sagredo A, Cañada FJ, Nieto O, Jimenez-Barbero J, Martín-Lomas M. Substrate specificity of small-intestinal lactase. Assessment of the role of the substrate hydroxyl groups. Eur J Biochem 1992; 209:415-22. [PMID: 1396715 DOI: 10.1111/j.1432-1033.1992.tb17304.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Lactase-phlorizin hydrolase is a disaccharidase present in the small intestine of mammals. This enzyme has two active sites, one being responsible for the hydrolysis of lactose. Lactase activity is thought to be selective towards glycosides with a hydrophilic aglycon. In this work, we report a systematic study on the importance of each hydroxyl group in the substrate molecule for lactase activity. For this purpose, all of the monodeoxy derivatives of methyl beta-lactoside and other lactose analogues are studied as lactase substrates. With respect to the galactose moiety, it is shown here that HO-3' and HO-2' are necessary for hydrolysis of the substrates by lactase. Using these chemically modified substrates, it has been confirmed that lactase does not behave as a typical beta-galactosidase, since it does not show an absolute selectivity with respect to substitution and stereochemistry at C4' in the galactose moiety of the substrate. However, the glucose moiety, in particular the HO-6, appears to be important for substrate hydrolysis, although none of the hydroxyl groups seemed to be essential. In order to differentiate both activities of the enzyme, a new assay for the phlorizin-hydrolase activity has also been developed.
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Affiliation(s)
- A Rivera-Sagredo
- Instituto de Química Orgánica, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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Tan EW, Pérez-Sala D, Cañada FJ, Rando RR. Identifying the recognition unit for G protein methylation. J Biol Chem 1991; 266:10719-22. [PMID: 1904056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Signal transducing G proteins, such as transducin, are prenylated and methylated at carboxyl-terminal cysteine residues. The methylation of transducin occurs by means of a membrane bound S-adenosyl methionine-dependent methyltransferase. This methyltransferase accepts the simple modified amino acid N-acetyl-S-farnesyl-L-cysteine (AFC) as a substrate. This means that the enzyme does not require peptide sequences of transducin in a putative substrate. Moreover, small structural changes in the AFC structural unit all lead to molecules incapable of being substrates. For example, neither N-acetyl-S-farnesylhomocysteine (AFHC) nor the saturated form of AFC are substrates. Interestingly, substitution of the N-acetyl moiety of AFC with a hydrogen atom leads to S-farnesylthiopropionic acid (FTP), which is an excellent substrate for the methyltransferase. The methyltransferase shows great specificity for the the FTP pharmacophore. So far, alterations in this structure have not led to active substrates. For example, removal of a methylene group of FTP, producing S-farnesylthioacetic acid (FTA), abolished substrate activity. FTA is a potent competitive inhibitor of the enzyme. FTP is thus the ultimately simplified substrate for the methyltransferase and does not contain any remnants of the peptide structure of transducin.
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Affiliation(s)
- E W Tan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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Pérez-Sala D, Tan EW, Cañada FJ, Rando RR. Methylation and demethylation reactions of guanine nucleotide-binding proteins of retinal rod outer segments. Proc Natl Acad Sci U S A 1991; 88:3043-6. [PMID: 1901651 PMCID: PMC51380 DOI: 10.1073/pnas.88.8.3043] [Citation(s) in RCA: 118] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Retinal transducin was previously shown to be farnesylated on its gamma subunit. This farnesylation reaction on a cysteine residue near the carboxyl terminus is followed by peptidase cleavage at the cysteine. Thus the modified cysteine becomes the carboxyl terminus. It is shown here that the free carboxyl group can be methylated by an S-adenosyl-L-methionine-dependent methyltransferase associated with the rod outer segment membranes. This process can be inhibited by S-adenosyl-L-homocysteine and sinefungin. Moreover, synthetic N-acetyl-S-farnesyl-L-cysteine, but not N-acetyl-L-cysteine, is a substrate for the enzyme. Rapid demethylation of N-acetyl-S-farnesyl-L-cysteine methyl ester can be observed in the membranes. Transducin is also enzymatically demethylated by the rod outer segment membranes. Moreover, the 23- to 29-kDa small G proteins are methylated and demethylated in this system. These data suggest that methylation/demethylation may play a regulatory role in visual signal transduction.
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Affiliation(s)
- D Pérez-Sala
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
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Cañada FJ, Law WC, Rando RR, Yamamoto T, Derguini F, Nakanishi K. Substrate specificities and mechanism in the enzymatic processing of vitamin A into 11-cis-retinol. Biochemistry 1990; 29:9690-7. [PMID: 2271609 DOI: 10.1021/bi00493a026] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The biosynthesis of 11-cis-retinol in the retinal pigment epithelium requires two consecutive enzymatic reactions. The first involves the esterification of all-trans-retinol by lecithin retinol acyltransferase (LRAT). The second reaction involves the direct conversion of an all-trans-retinyl ester into 11-cis-retinol by an isomerase-like enzyme. This latter reaction couples the free energy of hydrolysis of an ester to the thermodynamically uphill trans to cis conversion, thus providing the energy to drive the latter process. In this paper both enzymes are studied with respect to their substrate specificities to provide information on mechanism. The isomerase is shown to be highly specific with respect to the ionylidene ring system and substitution at C15, whereas sterically bulkier substituents at C9 and C11 are permitted. C5 and C13 demethyl retinoids are isomerized, removing from consideration isomerization mechanisms involving C-H abstraction at the C5 or C13 methyl groups of the retinoid. On the other hand, C9 demethyl retinoids are not isomerized. A C-H abstraction mechanism is unlikely at the C9 methyl group as well, because no kinetic deuterium isotope effect is found with all-trans-19,19,19-trideuterioretinoids and isomerization of unlabeled retinoids occurs without the incorporation of deuterium when the isomerization is performed in D2O. LRAT proved to be broadly specific for retinols but was relatively inert with other hydrophobic alcohols including cholesterol. The enzyme is also highly specific for phosphatidylcholine analogues versus other potential membranous acyl donors such as phosphatidylethanolamine and phosphatidylserine.
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Affiliation(s)
- F J Cañada
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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Abstract
Protein prenylation with farnesyl or geranylgeranyl moieties is an important posttranslational modification that affects the activity of such diverse proteins as the nuclear lamins, the yeast mating factor mata, and the ras oncogene products. In this article, we show that whole retinal cultures incorporate radioactive mevalonic acid into proteins of 23-26 kDa and one of 8 kDa. The former proteins are probably the "small" guanine nucleotide-binding regulatory proteins (G proteins) and the 8-kDa protein is the gamma subunit of the well-studied retinal heterotrimeric G protein (transducin). After deprenylating purified transducin and its subunits with Raney nickel or methyl iodide/base, the adducted prenyl group can be identified as an all-trans-farnesyl moiety covalently linked to a cysteine residue. Thus far, prenylation reactions have been found to occur at cysteine in a carboxyl-terminal consensus CAAX sequence, where C is the cysteine, A is an aliphatic amino acid, and X is undefined. Both the alpha and gamma subunits of transducin have this consensus sequence, but only the gamma subunit is prenylated. Therefore, the CAAX motif is not necessary and sufficient to direct prenylation. Finally, since transducin is the best understood G protein, both structurally and mechanistically, the discovery that it is farnesylated should allow for a quantitative understanding of this post-translational modification.
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Affiliation(s)
- R K Lai
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
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Abstract
Lecithin retinol acyl transferase (LRAT) from the retinyl pigment epithelium is potently inhibited by all-trans-retinyl alpha-bromoacetate in the micromolar range. The inhibition is competitive and reversible. The retinyl pigment epithelium also contains an enzymatic activity capable of converting added all-trans-retinol into 11-cis-retinol. This isomerization is likely to require the intermediate formation of all-trans-retinyl esters, which are themselves produced by LRAT action. Here this possibility is directly tested by studying the effect of all-trans-retinyl alpha-bromoacetate on the isomerization reaction. When pigment epithelium membranes are preincubated with all-trans-retinyl alpha-bromoacetate, they form neither retinyl esters nor 11-cis-retinol from added all-trans-retinol. However, if the pigment epithelium membranes are first allowed to form all-trans-retinyl esters from all-trans-retinol before the addition of all-trans-retinyl alpha-bromoacetate, then 11-cis-retinol formation proceeds at close to the rate found in the absence of inhibitor. In addition, 11-cis-retinyl esters are not formed under these conditions, eliminating the possibility of a direct ester-ester isomerization route. Therefore, all-trans-retinyl esters are obligate intermediates in the biosynthesis of 11-cis-retinol.
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Affiliation(s)
- A Trehan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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Barry RJ, Cañada FJ, Rando RR. Solubilization and partial purification of retinyl ester synthetase and retinoid isomerase from bovine ocular pigment epithelium. J Biol Chem 1989; 264:9231-8. [PMID: 2722827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Studies reported previously from this laboratory have demonstrated that membranes from the pigment epithelium of the vertebrate eye can transform free all-trans-retinol to 11-cis-retinol as well as 11-cis- and all trans-retinyl esters (Bernstein, P. S., Law, W. C., and Rando, R. R. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 1849-1853; Bernstein, P. S., Law, W. C., and Rando, R. R. (1987) J. Biol. Chem. 262, 16848-16857; Fulton, B. S., and Rando, R. R. (1987) Biochemistry 26, 7938-7945). The congeneric retinals are also formed under conditions where retinol redox activity is present. Here we report the successful solubilization of both the retinyl ester synthetase and isomerase activities from the pigment epithelium membranes of the bovine eye. The zwitterionic detergent Zwittergent 3-14(N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate; cmc 0.012%) gave optimal solubilization of both activities. Three initial criteria for successful solubilization were used. First, high speed centrifugation (greater than 150,000 x g) left the activities in the supernatant. Second, the solubilized enzymatic activities were found in the included volume upon gel filtration. Finally, the solubilized activities were quantitatively passed through a 0.22-microns filter. Employing anion exchange and gel filtration chromatography results in a partial purification of the retinyl ester synthetase (approximately 189-fold). The solubilized retinoid isomerase is also partially purified (approximately 10-14-fold) following anion exchange chromatography. It is also shown that the membrane-bound and solubilized ester synthetase catalyzes the esterification of retinol using added lecithins as exogenous acyl donors. In addition, evidence is provided indicating that there is a positional selectivity for the acyl group transfer from the lecithin to retinol. The transfer occurs largely, if not entirely, from the 1-position of the lecithin.
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Affiliation(s)
- R J Barry
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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Barry RJ, Cañada FJ, Rando RR. Solubilization and Partial Purification of Retinyl Ester Synthetase and Retinoid Isomerase from Bovine Ocular Pigment Epithelium. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)60519-8] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Abstract
The eye needs to biosynthesize 11-cis-retinoids because the chromophore of rhodopsin is 11-cis-retinal. The critical metabolic step is the endergonic isomerization of free all-trans-retinol (vitamin A) into 11-cis-retinol. This isomerization process can take place in isolated membranes from the retinal pigment epithelium in the absence of added energy sources. Specific binding proteins probably do not serve as an energy source, and since all of the reactions in the visual cycle are shown here to be reversible, trapping reactions also do not participate in the isomerization reaction. One previously unexplored possibility is that the chemical energy in the bonds of the membrane itself may drive the isomerization reaction. A group transfer reaction is proposed that forms a retinyl ester from a lipid acyl donor and vitamin A. This transfer can drive the isomerization reaction because the all-trans-retinyl ester is isomerized directly to 11-cis-retinol. Thus, the free energy of hydrolysis of the ester is coupled to the thermodynamically uphill trans to cis isomerization. The prediction of an obligate C-O bond cleavage in the vitamin A moiety during isomerization is borne out. Although the natural substrate for isomerization is not known, all-trans-retinyl palmitate is processed in vitro to 11-cis-retinol by pigment epithelial membranes.
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Affiliation(s)
- P S Deigner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
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Pisabarro AG, Cañada FJ, Vázquez D, Arriaga P, Rodríguez-Tébar A. Structural modification of Escherichia coli peptidoglycan induced by bicyclomycin. J Antibiot (Tokyo) 1986; 39:914-21. [PMID: 3531129 DOI: 10.7164/antibiotics.39.914] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We have studied the modification of Escherichia coli peptidoglycan induced by bicyclomycin. For this purpose liquid chromatography for peptidoglycan analysis has been used. The main alteration found was an increase of diaminopimelyl-diaminopimelyl bridge containing subunits. Our results show that bicyclomycin impairs the normal breakage of that interpeptidic bond, whose cleavage is needed for the normal remodeling of peptidoglycan and cell growth. Based on the analysis of the possible structure of diaminopimelyl-diaminopimelyl bond and bicyclomycin, we propose a hypothesis on the mechanism of action of bicyclomycin.
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