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Barone V. Accurate structures and spectroscopic parameters of α,α-dialkylated α-amino acids in the gas-phase: a joint venture of DFT and wave-function composite methods. Phys Chem Chem Phys 2023; 25:22768-22774. [PMID: 37591810 DOI: 10.1039/d3cp02503a] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
Accurate computations of structural, conformational and spectroscopic properties in the gas phase have been performed for two α,α-dialkylated α-amino acids, namely aminoisobutyric acid and cyclopropylglycine. Thanks to the integration of modern double hybrid functionals and wave-function methods, several low-energy structures of the title molecules could be analyzed employing standard computer resources. The computed features of all the most stable conformers of the target amino acids closely match the corresponding spectroscopic parameters issued from microwave spectroscopic studies in the gas-phase. Together with their intrinsic interest, the accuracy of the results obtained with reasonable computer times paves the way for accurate investigations of other flexible bricks of life.
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Affiliation(s)
- Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy.
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2
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Heath SL, Horne WS, Lengyel GA. Effects of chirality and side chain length in C α,α-dialkylated residues on β-hairpin peptide folded structure and stability. Org Biomol Chem 2023; 21:6320-6324. [PMID: 37503895 PMCID: PMC10445279 DOI: 10.1039/d3ob00963g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Strategic incorporation of achiral Cα,α-dialkylated amino acids with bulky substituents into peptides can be used to promote extended strand conformations and inhibit protein-protein interactions associated with amyloid formation. In this work, we evaluate the thermodynamic impact of chiral Cα,α monomers on folding preferences in such systems through introduction of a series of Cα-methylated and Cα-ethylated residues into a β-hairpin host sequence. Depending on stereochemical configuration of the artificial monomer and potential for additional hydrophobic packing, a Cα-ethyl-Cα-propyl glycine residue can provide similar or enhanced folded stability relative to an achiral Cα,α-diethyl analogue.
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Affiliation(s)
- Shelby L Heath
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - W Seth Horne
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - George A Lengyel
- Department of Chemistry, Slippery Rock University, Slippery Rock, PA 16057, USA.
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3
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Fournes F, Niault T, Czarnecki J, Tissier-Visconti A, Mazel D, Val ME. The coordinated replication of Vibrio cholerae's two chromosomes required the acquisition of a unique domain by the RctB initiator. Nucleic Acids Res 2021; 49:11119-11133. [PMID: 34643717 PMCID: PMC8565311 DOI: 10.1093/nar/gkab903] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 08/30/2021] [Accepted: 09/22/2021] [Indexed: 12/21/2022] Open
Abstract
Vibrio cholerae, the pathogenic bacterium that causes cholera, has two chromosomes (Chr1, Chr2) that replicate in a well-orchestrated sequence. Chr2 initiation is triggered only after the replication of the crtS site on Chr1. The initiator of Chr2 replication, RctB, displays activities corresponding with its different binding sites: initiator at the iteron sites, repressor at the 39m sites, and trigger at the crtS site. The mechanism by which RctB relays the signal to initiate Chr2 replication from crtS is not well-understood. In this study, we provide new insights into how Chr2 replication initiation is regulated by crtS via RctB. We show that crtS (on Chr1) acts as an anti-inhibitory site by preventing 39m sites (on Chr2) from repressing initiation. The competition between these two sites for RctB binding is explained by the fact that RctB interacts with crtS and 39m via the same DNA-binding surface. We further show that the extreme C-terminal tail of RctB, essential for RctB self-interaction, is crucial for the control exerted by crtS. This subregion of RctB is conserved in all Vibrio, but absent in other Rep-like initiators. Hence, the coordinated replication of both chromosomes likely results from the acquisition of this unique domain by RctB.
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MESH Headings
- Amino Acid Sequence
- Bacterial Proteins/chemistry
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Base Sequence
- Binding Sites
- Binding, Competitive
- Chromosomes, Bacterial/chemistry
- Chromosomes, Bacterial/metabolism
- Cloning, Molecular
- DNA Replication
- DNA, Bacterial/genetics
- DNA, Bacterial/metabolism
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Gene Expression Regulation, Bacterial
- Genetic Vectors/chemistry
- Genetic Vectors/metabolism
- Models, Molecular
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Interaction Domains and Motifs
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Replication Origin
- Sequence Alignment
- Sequence Homology, Amino Acid
- Signal Transduction
- Vibrio cholerae/genetics
- Vibrio cholerae/metabolism
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Affiliation(s)
- Florian Fournes
- Institut Pasteur, Université de Paris, Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Paris 75015, France
- Centre National de la Recherche Scientifique, UMR3525, Paris 75015, France
| | - Theophile Niault
- Institut Pasteur, Université de Paris, Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Paris 75015, France
- Centre National de la Recherche Scientifique, UMR3525, Paris 75015, France
- Sorbonne Université, Collège Doctoral, Paris 75005, France
| | - Jakub Czarnecki
- Institut Pasteur, Université de Paris, Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Paris 75015, France
- Centre National de la Recherche Scientifique, UMR3525, Paris 75015, France
- University of Warsaw, Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, Warsaw 02-096, Poland
| | - Alvise Tissier-Visconti
- Institut Pasteur, Université de Paris, Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Paris 75015, France
- Centre National de la Recherche Scientifique, UMR3525, Paris 75015, France
| | - Didier Mazel
- Institut Pasteur, Université de Paris, Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Paris 75015, France
- Centre National de la Recherche Scientifique, UMR3525, Paris 75015, France
| | - Marie-Eve Val
- Institut Pasteur, Université de Paris, Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Paris 75015, France
- Centre National de la Recherche Scientifique, UMR3525, Paris 75015, France
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4
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Brown CJ, Verma CS, Lane DP, Lama D. Conformational ordering of intrinsically disordered peptides for targeting translation initiation. Biochim Biophys Acta Gen Subj 2020; 1865:129775. [PMID: 33122085 DOI: 10.1016/j.bbagen.2020.129775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/14/2020] [Accepted: 10/22/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND Intrinsically disordered regions (IDRs) in proteins can regulate their activity by facilitating protein-protein interactions (PPIs) as exemplified in the recruitment of the eukaryotic translation initiation factor 4E (eIF4E) protein by the protein eIF4G. Deregulation of this PPI module is central to a broad spectrum of cancer related malignancies and its targeted inhibition through bioactive peptides is a promising strategy for therapeutic intervention. METHODS We employed molecular dynamics simulations coupled with biophysical assays to rationally develop peptide derivatives from the intrinsically disordered eIF4G scaffold by incorporating non-natural amino acids that facilitates disorder-to-order transition. RESULTS The conformational heterogeneity of these peptides and the degree of structural reorganization required to adopt the optimum mode of interaction with eIF4E underscores their differential binding affinities. The presence of a pre-structured local helical element in the ensemble of structures was instrumental in the efficient docking of the peptides on to the protein surface. The formation of Y4: P38 hydrogen-bond interaction between the peptide and eIF4E is a rate limiting event in the efficient recognition of the protein since it occurs through the disordered region of the peptide. CONCLUSIONS These insights were exploited to further design features into the peptide to propagate bound-state conformations in solution which resulted in the generation of a potent eIF4E binder. GENERAL SIGNIFICANCE The study illustrates the molecular basis of eIF4E recognition by a disordered epitope from eIF4G and its modulation to generate peptides that can potentially attenuate translation initiation in oncology.
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Affiliation(s)
- Christopher J Brown
- p53 Laboratory, A*STAR (Agency for Science, Technology and Research), 8A Biomedical Grove, #06-04/05, Neuros/Immunos, 138648, Singapore.
| | - Chandra S Verma
- Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), 30 Biopolis Street, #07-01 Matrix, 138671, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543, Singapore; School of Biological Sciences, Nanyang Technological University, 50 Nanyang Drive, 637551, Singapore
| | - David P Lane
- p53 Laboratory, A*STAR (Agency for Science, Technology and Research), 8A Biomedical Grove, #06-04/05, Neuros/Immunos, 138648, Singapore; Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Biomedicum Quarter 7B-C Solnavägen 9, 17165 Solna, Sweden
| | - Dilraj Lama
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Biomedicum Quarter 7B-C Solnavägen 9, 17165 Solna, Sweden.
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5
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Evaluation of the Antimicrobial Activity of Cationic Peptides Loaded in Surface-Modified Nanoliposomes against Foodborne Bacteria. Int J Mol Sci 2019; 20:ijms20030680. [PMID: 30764495 PMCID: PMC6386929 DOI: 10.3390/ijms20030680] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/31/2019] [Accepted: 02/02/2019] [Indexed: 01/03/2023] Open
Abstract
Bacteria are a common group of foodborne pathogens presenting public health issues with a large economic burden for the food industry. Our work focused on a solution to this problem by evaluating antibiotic activity against two bacteria (Listeria monocytogenes and Escherichia coli) of relevance in the field of foodstuffs. We used two approaches: (i) structural modification of the antimicrobial peptides and (ii) nano-vehiculisation of the modified peptides into polymer-coated liposomes. To achieve this, two antimicrobial peptides, herein named ‘peptide +2′ and ‘peptide +5′ were synthesised using the solid phase method. The physicochemical characterisation of the peptides was carried out using measurements of surface tension and dynamic light scattering. Additionally, nanoliposomes were elaborated by the ethanol injection method and coated with a cationic polymer (Eudragit E-100) through the layer-by-layer process. Liposome characterisation, in terms of size, polydispersity and zeta potential, was undertaken using dynamic light scattering. The results show that the degree of hydrophilic modification in the peptide leads to different characteristics of amphipathicity and subsequently to different physicochemical behaviour. On the other hand, antibacterial activity against both bacteria was slightly altered after modifying peptide sequence. Nonetheless, after the encapsulation of the peptides into polymer-coated nano-liposomes, the antibacterial activity increased approximately 2000-fold against that of L. monocytogenes.
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6
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Alonso JL, Peña I, López JC, Alonso ER, Vaquero V. The Shape of the Simplest Non-proteinogenic Amino Acid α-Aminoisobutyric Acid (Aib). Chemistry 2019; 25:2288-2294. [DOI: 10.1002/chem.201805038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 11/09/2018] [Indexed: 11/12/2022]
Affiliation(s)
- José L. Alonso
- Grupo de Espectroscopía Molecular (GEM); Edificio Quifima; Laboratorio de Espectroscopia y Bioespectroscopia; Unidad Asociada CSIC; Parque Científico Uva; Universidad de Valladolid; 47011 Valladolid Spain
| | - Isabel Peña
- Grupo de Espectroscopía Molecular (GEM); Edificio Quifima; Laboratorio de Espectroscopia y Bioespectroscopia; Unidad Asociada CSIC; Parque Científico Uva; Universidad de Valladolid; 47011 Valladolid Spain
| | - Juan C. López
- Departamento de Química Física e Inorgánica; Facultad de, Ciencias; Universidad de Valladolid; 47011 Valladolid Spain
| | - Elena R. Alonso
- Grupo de Espectroscopía Molecular (GEM); Edificio Quifima; Laboratorio de Espectroscopia y Bioespectroscopia; Unidad Asociada CSIC; Parque Científico Uva; Universidad de Valladolid; 47011 Valladolid Spain
| | - Vanesa Vaquero
- Grupo de Espectroscopía Molecular (GEM); Edificio Quifima; Laboratorio de Espectroscopia y Bioespectroscopia; Unidad Asociada CSIC; Parque Científico Uva; Universidad de Valladolid; 47011 Valladolid Spain
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7
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Arachchige D, Holub JM. Synthesis and Biological Activity of Scyllatoxin-Based BH3 Domain Mimetics Containing Two Disulfide Linkages. Protein J 2018; 37:428-443. [PMID: 30128635 DOI: 10.1007/s10930-018-9791-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The B cell lymphoma 2 (BCL2) proteins are a family of evolutionarily related proteins that act as positive or negative regulators of the intrinsic apoptosis pathway. Overexpression of anti-apoptotic BCL2 proteins in cells is associated with apoptotic resistance, which can result in cancerous phenotypes and pathogenic cell survival. Consequently, anti-apoptotic BCL2 proteins have attracted considerable interest as therapeutic targets. We recently reported the development of a novel class of synthetic protein based on scyllatoxin (ScTx) designed to mimic the helical BH3 interaction domain of the pro-apoptotic BCL2 protein Bax. These studies showed that the number and position of native disulfide linkages contained within the ScTx-Bax structure significantly influences the ability for these constructs to target anti-apoptotic BCL2 proteins in vitro. The goal of the present study is to investigate the contribution of two disulfide linkages in the folding and biological activity of ScTx-Bax proteins. Here, we report the full chemical synthesis of three ScTx-Bax sequence variants, each presenting two native disulfide linkages at different positions within the folded structure. It was observed that two disulfide linkages were sufficient to fold ScTx-Bax proteins into native-like architectures reminiscent of wild-type ScTx. Furthermore, we show that select (bis)disulfide ScTx-Bax variants can target Bcl-2 (proper) in vitro and that the position of the disulfide bonds significantly influences binding affinity. Despite exhibiting only modest binding to Bcl-2, the successful synthesis of ScTx-Bax proteins containing two disulfide linkages represents a viable route to ScTx-based BH3 domain mimetics that preserve native-like conformations. Finally, structural models of ScTx-Bax proteins in complex with Bcl-2 indicate that these helical mimetics bind in similar configurations as wild-type Bax BH3 domains. Taken together, these results suggest that ScTx-Bax proteins may serve as potent lead compounds that expand the repertoire of "druggable" protein-protein interactions.
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Affiliation(s)
- Danushka Arachchige
- Department of Chemistry and Biochemistry, Ohio University, Biochemistry Research Facility 108, 350 W. State St., Athens, OH, 45701, USA
| | - Justin M Holub
- Department of Chemistry and Biochemistry, Ohio University, Biochemistry Research Facility 108, 350 W. State St., Athens, OH, 45701, USA.
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, 45701, USA.
- Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA.
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8
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Jaguva Vasudevan AA, Hofmann H, Willbold D, Häussinger D, Koenig BW, Münk C. Enhancing the Catalytic Deamination Activity of APOBEC3C Is Insufficient to Inhibit Vif-Deficient HIV-1. J Mol Biol 2017; 429:1171-1191. [DOI: 10.1016/j.jmb.2017.03.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 03/08/2017] [Accepted: 03/08/2017] [Indexed: 12/17/2022]
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9
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Harris MM, Coon Z, Alqaeisoom N, Swords B, Holub JM. Targeting anti-apoptotic Bcl2 proteins with scyllatoxin-based BH3 domain mimetics. Org Biomol Chem 2016; 14:440-446. [PMID: 26563651 DOI: 10.1039/c5ob02080h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BH3 domain mimetics based on the small protein scyllatoxin (ScTx) were designed to target the anti-apoptotic protein Bcl2 in vitro. Intrinsically disordered ScTx variants were found to bind Bcl2 with nanomolar affinity, indicating that an induced fit binding mechanism is required for favorable BH3 : Bcl2 interaction.
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Affiliation(s)
- M Margaret Harris
- Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA.
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10
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Maffucci I, Clayden J, Contini A. Origin of Helical Screw Sense Selectivity Induced by Chiral Constrained Cα-Tetrasubstituted α-Amino Acids in Aib-based Peptides. J Phys Chem B 2015; 119:14003-13. [PMID: 26457452 DOI: 10.1021/acs.jpcb.5b07050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The mechanisms behind the propensity of chiral constrained Cα-tetrasubstituted amino acids (cCTAAs) to induce one particular helical screw sense, when included in the Ac-Aib2-cCTAA-Aib2-NHMe peptide model, were studied through replica exchange molecular dynamics, potential of mean force, and quantum theory of atoms in molecules calculations. We observed that cCTAAs exert their effect on helical screw sense selectivity through the positioning of the side chain to generate steric hindrance in either the (-x, +y, +z) or (+x, +y, -z) sectors of a right-handed 3D Cartesian space, where the z axis corresponds to the axis of the helix and the Cα lies on the +y semiaxis (0, +y, 0). The different strengthening of the noncovalent interactions, also comprising C-H···O interactions, exerted by the cCTAA in the right-handed or left-handed helix was also found important to define the preference of a cCTAA for a particular helix screw sense.
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Affiliation(s)
- Irene Maffucci
- Dipartimento di Scienze Farmaceutiche - Sezione di Chimica Generale e Organica "Alessandro Marchesini", Università degli Studi di Milano , Via Venezian, 21, 20133 Milano, Italy
| | - Jonathan Clayden
- School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, U.K
| | - Alessandro Contini
- Dipartimento di Scienze Farmaceutiche - Sezione di Chimica Generale e Organica "Alessandro Marchesini", Università degli Studi di Milano , Via Venezian, 21, 20133 Milano, Italy
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11
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Weber S, Salabei JK, Möller G, Kremmer E, Bhatnagar A, Adamski J, Barski OA. Aldo-keto Reductase 1B15 (AKR1B15): a mitochondrial human aldo-keto reductase with activity toward steroids and 3-keto-acyl-CoA conjugates. J Biol Chem 2015; 290:6531-45. [PMID: 25577493 DOI: 10.1074/jbc.m114.610121] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aldo-keto reductases (AKRs) comprise a superfamily of proteins involved in the reduction and oxidation of biogenic and xenobiotic carbonyls. In humans, at least 15 AKR superfamily members have been identified so far. One of these is a newly identified gene locus, AKR1B15, which clusters on chromosome 7 with the other human AKR1B subfamily members (i.e. AKR1B1 and AKR1B10). We show that alternative splicing of the AKR1B15 gene transcript gives rise to two protein isoforms with different N termini: AKR1B15.1 is a 316-amino acid protein with 91% amino acid identity to AKR1B10; AKR1B15.2 has a prolonged N terminus and consists of 344 amino acid residues. The two gene products differ in their expression level, subcellular localization, and activity. In contrast with other AKR enzymes, which are mostly cytosolic, AKR1B15.1 co-localizes with the mitochondria. Kinetic studies show that AKR1B15.1 is predominantly a reductive enzyme that catalyzes the reduction of androgens and estrogens with high positional selectivity (17β-hydroxysteroid dehydrogenase activity) as well as 3-keto-acyl-CoA conjugates and exhibits strong cofactor selectivity toward NADP(H). In accordance with its substrate spectrum, the enzyme is expressed at the highest levels in steroid-sensitive tissues, namely placenta, testis, and adipose tissue. Placental and adipose expression could be reproduced in the BeWo and SGBS cell lines, respectively. In contrast, AKR1B15.2 localizes to the cytosol and displays no enzymatic activity with the substrates tested. Collectively, these results demonstrate the existence of a novel catalytically active AKR, which is associated with mitochondria and expressed mainly in steroid-sensitive tissues.
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Affiliation(s)
- Susanne Weber
- From the Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Experimental Genetics, Genome Analysis Center, 85764 Neuherberg, Germany
| | - Joshua K Salabei
- the Diabetes and Obesity Center, School of Medicine, University of Louisville, Louisville, Kentucky 40202
| | - Gabriele Möller
- From the Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Experimental Genetics, Genome Analysis Center, 85764 Neuherberg, Germany
| | - Elisabeth Kremmer
- the Institute of Molecular Immunology, German Research Center for Environmental Health, Helmholtz Zentrum Muenchen, 81377 Muenchen, Germany
| | - Aruni Bhatnagar
- the Diabetes and Obesity Center, School of Medicine, University of Louisville, Louisville, Kentucky 40202
| | - Jerzy Adamski
- From the Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Experimental Genetics, Genome Analysis Center, 85764 Neuherberg, Germany, the Lehrstuhl für Experimentelle Genetik, Technische Universitaet Muenchen, 85356 Freising-Weihenstephan, Germany, and the German Center for Diabetes Research, 85764 Neuherberg, Germany
| | - Oleg A Barski
- the Diabetes and Obesity Center, School of Medicine, University of Louisville, Louisville, Kentucky 40202,
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12
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Iqbal Z, Shahzad M, Vissers LELM, van Scherpenzeel M, Gilissen C, Razzaq A, Zahoor MY, Khan SN, Kleefstra T, Veltman JA, de Brouwer APM, Lefeber DJ, van Bokhoven H, Riazuddin S. A compound heterozygous mutation in DPAGT1 results in a congenital disorder of glycosylation with a relatively mild phenotype. Eur J Hum Genet 2012; 21:844-9. [PMID: 23249953 DOI: 10.1038/ejhg.2012.257] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 10/05/2012] [Accepted: 10/11/2012] [Indexed: 01/07/2023] Open
Abstract
Congenital disorders of glycosylation (CDG) are a large group of recessive multisystem disorders caused by impaired protein or lipid glycosylation. The CDG-I subgroup is characterized by protein N-glycosylation defects originating in the endoplasmic reticulum. The genetic defect is known for 17 different CDG-I subtypes. Patients in the few reported DPAGT1-CDG families exhibit severe intellectual disability (ID), epilepsy, microcephaly, severe hypotonia, facial dysmorphism and structural brain anomalies. In this study, we report a non-consanguineous family with two affected adults presenting with a relatively mild phenotype consisting of moderate ID, epilepsy, hypotonia, aggressive behavior and balance problems. Exome sequencing revealed a compound heterozygous missense mutation, c.85A>T (p.I29F) and c.503T>C (p.L168P), in the DPAGT1 gene. The affected amino acids are located in the first and fifth transmembrane domains of the protein. Isoelectric focusing and high-resolution mass spectrometry analyses of serum transferrin revealed glycosylation profiles that are consistent with a CDG-I defect. Our results show that the clinical spectrum of DPAGT1-CDG is much broader than appreciated so far.
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Affiliation(s)
- Zafar Iqbal
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
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13
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Pellegrino S, Contini A, Clerici F, Gori A, Nava D, Gelmi ML. 1H-Azepine-4-amino-4-carboxylic acid: a new α,α-disubstituted ornithine analogue capable of inducing helix conformations in short Ala-Aib pentapeptides. Chemistry 2012; 18:8705-15. [PMID: 22689465 DOI: 10.1002/chem.201104023] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/30/2012] [Indexed: 11/08/2022]
Abstract
A very efficient synthesis of orthogonally protected 1H-azepine-4-amino-4-carboxylic acid, abbreviated as Azn, a conformationally restricted analogue of ornithine, was realized. It was obtained on a gram scale in good overall yield in five steps, three of which did not require isolation of the intermediates, starting from the readily available 1-amino-4-oxo-cyclohexane-4-carboxylic acid. Both enantiomers were used for the preparation of pentapeptide models containing Ala, Aib, and Azn. Conformational studies using both spectroscopic techniques (NMR, CD) and molecular dynamics on model 5-mer peptides showed that the (R)-Azn isomer possesses a marked helicogenic effect.
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Affiliation(s)
- Sara Pellegrino
- DISMAB, Sezione di Chimica Organica A. Marchesini, Facoltà di Farmacia, Università degli Studi Milano, Via Venezian 21, 20133 Milano, Italy.
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