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Islam SM, Havranek B, Ibnat Z, Roy PN. New Insights into the Role of Hydrogen Bonding in Furanoside Binding to Protein. J Phys Chem B 2020; 124:1919-1927. [PMID: 32075374 DOI: 10.1021/acs.jpcb.9b11924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Furanosides have been subjected to extensive studies owing to their inherent flexibility, which is believed to play an important role in the survival and pathogenicity of different disease-causing organisms in the human body. This study reports the binding free energy (ΔG) and specificity of arabinofuranose oligosaccharides to a protein, arabinanase (Arb43A), with the use of potential of mean force (PMF) calculations using the umbrella-sampling simulations. Long molecular dynamics simulations have been carried out to understand intermolecular interactions in the arabinofuranose-protein complex. The PMF for pulling the α-(1 → 5)-linked L-arabinohexaose (ligand) from the protein provides a large free energy of binding, -16.8 kcal/mol. The ΔG of the nonreducing arabinotriose end is found to be -12.6 kcal/mol, while the ΔG of the reducing end is calculated to be -7.7 kcal/mol. In the absence of nonreducing arabinotrioside, the ΔG of the reducing arabinotrioside is -8.5 kcal/mol. Similarly, in the absence of reducing arabinotrioside, the ΔG of the nonreducing arabinotrioside is calculated to be -9.4 kcal/mol. The main contributing factor in the protein-arabinofuranose binding is hydrogen bonding. Acidic amino acid residues, Glu and Asp, with furanosides produce the strongest hydrogen bonding. Araf-A, B, and C construct the reducing arabinotriose, while Araf-D, E, and F construct the nonreducing arabinotriose. Since most of the hydrogen-bonding occupancies belong to Araf-D and Araf-E, the nonreducing arabinotriose is bound to protein more strongly than the reducing arabinotriose. This explains why the reducing arabinotriose can detach from the protein in nature.
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Affiliation(s)
- Shahidul M Islam
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Brandon Havranek
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Zahin Ibnat
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Pierre-Nicholas Roy
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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2
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Fan Q, Tan H, Wang Y, Song X, Yan H. Conformational analysis of ticagrelor: effect of noncovalent interaction on conformational population. Struct Chem 2018. [DOI: 10.1007/s11224-018-1143-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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3
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Walczak D, Nowacki A, Trzybiński D, Samaszko-Fiertek J, Myszka H, Sikorski A, Liberek B. Conformational studies of N-(α-d-glucofuranurono-6,3-lactone)- and N-(methyl β-d-glucopyranuronate)-p-nitroanilines. Carbohydr Res 2017; 446-447:85-92. [PMID: 28554013 DOI: 10.1016/j.carres.2017.05.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 04/28/2017] [Accepted: 05/13/2017] [Indexed: 10/19/2022]
Abstract
N-(α-d-Glucofuranurono-6,3-lactone)-p-nitroaniline and N-(methyl β-d-glucopyranuronate)-p-nitroaniline were obtained as crystalline solids. The single-crystal X-ray diffraction, NMR data and DFT calculations for N-(α-d-glucofuranurono-6,3-lactone)-p-nitroaniline indicate that this N-furanoside adopts a 3T2/3E-like conformation in the crystal lattice, solution and gas phase. Thus, the structure of recorded for N-furanoside 1H NMR spectrum is indicative of the 3T2/3E region of the pseudorotational itinerary for furanose derivatives with α-d-gluco, β-L-ido and α-d-xylo configurations. Moreover, it is concluded that the 1T2/E2/3T2/3E region of the pseudorotational itinerary for furanose derivatives with d-gluco, L-ido and d-xylo configurations should be characterised by the lack of coupling between H2 and H3 protons, irrespective of the anomeric configuration. Such a lack of vicinal coupling is characteristic for some of the trans-oriented furanose ring protons. The single-crystal X-ray diffraction and NMR data for N-(methyl β-d-glucopyranuronate)-p-nitroaniline indicate that this N-glucuronide adopts the 4C1 conformation, both in the crystal lattice and solution. The occurrence of anomeric effects in the presented N-glycosides is discussed. The crystal structure analysis of both N-glycosides gives evidence that the amine group in p-nitroaniline is planar due to the nitrogen sp2 hybridisation.
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Affiliation(s)
- Dominik Walczak
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Andrzej Nowacki
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Damian Trzybiński
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland; Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | | | - Henryk Myszka
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Artur Sikorski
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Beata Liberek
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
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Suárez-Ortiz GA, Cerda-García-Rojas CM, Fragoso-Serrano M, Pereda-Miranda R. Complementarity of DFT Calculations, NMR Anisotropy, and ECD for the Configurational Analysis of Brevipolides K-O from Hyptis brevipes. JOURNAL OF NATURAL PRODUCTS 2017; 80:181-189. [PMID: 28099005 DOI: 10.1021/acs.jnatprod.6b00953] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Brevipolides K-O (1-5), five new cytotoxic 6-(6'-cinnamoyloxy-2',5'-epoxy-1'-hydroxyheptyl)-5,6-dihydro-2H-pyran-2-ones (IC50 values against six cancer cell lines, 1.7-10 μM), were purified by recycling HPLC from Hyptis brevipes. The structures, containing a distinctive tetrahydrofuran ring, were established by comprehensive quantum mechanical calculations and experimental spectroscopic analysis of their NMR and ECD data. Detailed analysis of the experimental NMR 1H-1H vicinal coupling constants in comparison with the corresponding DFT-calculated values at the B3LYP/DGDZVP level confirmed the absolute configuration of 3 and revealed its conformational preferences, which were further strengthened by NOESY correlations. NMR anisotropy experiments by the application of Mosher's ester methodology and chemical correlations were also used to conclude that this novel brevipolide series (1-5) share the same absolute configuration corresponding to C-6(R), C-1'(S), C-2'(R), C-5'(S), and C-6'(S).
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Affiliation(s)
- G Alejandra Suárez-Ortiz
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Circuito Exterior Ciudad Universitaria , Mexico City 04510, Mexico
| | - Carlos M Cerda-García-Rojas
- Departamento de Química, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional , A. P. 14-740, Mexico City 07000, Mexico
| | - Mabel Fragoso-Serrano
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Circuito Exterior Ciudad Universitaria , Mexico City 04510, Mexico
| | - Rogelio Pereda-Miranda
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Circuito Exterior Ciudad Universitaria , Mexico City 04510, Mexico
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Taha HA, Castillo N, Roy PN, Lowary TL. Conformational Studies of Methyl β-d-Arabinofuranoside Using the AMBER/GLYCAM Approach. J Chem Theory Comput 2015; 5:430-8. [PMID: 26610115 DOI: 10.1021/ct800384h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Furanosides are important constituents of a number of glycoconjugates from many microorganisms. The highly flexible nature of these furanosyl moieties is believed to contribute significantly to their role in biological processes. Therefore, an understanding of the conformational preferences of these molecules is an important area of research. As part of a larger program involved in the conformational analysis of mycobacterial oligofuranosides, molecular dynamics simulations on methyl β-d-arabinofuranoside (3) have been carried out using the AMBER forcefield and the GLYCAM carbohydrate parameter set. This approach was used to predict the rotamer population distribution about the hydroxymethyl group (C4-C5 bond) as well as the ring puckering of this flexible ring system. Comparison of the conformer distributions obtained during the simulation of 3 using the TIP3P water model with those obtained by analysis of (1)H-(1)H coupling constant data indicated that this water model was insufficient to describe the solvation of this system. However, the use of the TIP4P and TIP5P models led to improved agreement with conformer populations obtained from NMR data.
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Affiliation(s)
- Hashem A Taha
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Norberto Castillo
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Pierre-Nicholas Roy
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Todd L Lowary
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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Jana M, MacKerell AD. CHARMM Drude Polarizable Force Field for Aldopentofuranoses and Methyl-aldopentofuranosides. J Phys Chem B 2015; 119:7846-59. [PMID: 26018564 DOI: 10.1021/acs.jpcb.5b01767] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
An empirical all-atom CHARMM polarizable force filed for aldopentofuranoses and methyl-aldopentofuranosides based on the classical Drude oscillator is presented. A single electrostatic model is developed for eight different diastereoisomers of aldopentofuranoses by optimizing the existing electrostatic and bonded parameters as transferred from ethers, alcohols, and hexopyranoses to reproduce quantum mechanical (QM) dipole moments, furanose-water interaction energies and conformational energies. Optimization of selected electrostatic and dihedral parameters was performed to generate a model for methyl-aldopentofuranosides. Accuracy of the model was tested by reproducing experimental data for crystal intramolecular geometries and lattice unit cell parameters, aqueous phase densities, and ring pucker and exocyclic rotamer populations as obtained from NMR experiments. In most cases the model is found to reproduce both QM data and experimental observables in an excellent manner, whereas for the remainder the level of agreement is in the satisfactory regimen. In aqueous phase simulations the monosaccharides have significantly enhanced dipoles as compared to the gas phase. The final model from this study is transferrable for future studies on carbohydrates and can be used with the existing CHARMM Drude polarizable force field for biomolecules.
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Affiliation(s)
- Madhurima Jana
- †Department of Pharmaceutical Sciences, University of Maryland, 20 Penn Street HSF II, Baltimore, Maryland 21201, United States.,‡Department of Chemistry, National Institute of Technology Rourkela, Rourkela 769008, Odisha, India
| | - Alexander D MacKerell
- †Department of Pharmaceutical Sciences, University of Maryland, 20 Penn Street HSF II, Baltimore, Maryland 21201, United States
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7
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Taha HA, Richards MR, Lowary TL. Conformational Analysis of Furanoside-Containing Mono- and Oligosaccharides. Chem Rev 2012; 113:1851-76. [DOI: 10.1021/cr300249c] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Hashem A. Taha
- Alberta Glycomics Centre and Department of Chemistry, Gunning−Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2
| | - Michele R. Richards
- Alberta Glycomics Centre and Department of Chemistry, Gunning−Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2
| | - Todd L. Lowary
- Alberta Glycomics Centre and Department of Chemistry, Gunning−Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2
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8
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Islam SM, Roy PN. Performance of the SCC-DFTB Model for Description of Five-Membered Ring Carbohydrate Conformations: Comparison to Force Fields, High-Level Electronic Structure Methods, and Experiment. J Chem Theory Comput 2012; 8:2412-23. [DOI: 10.1021/ct200789w] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Shahidul M. Islam
- Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Pierre-Nicholas Roy
- Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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Abstract
Seven-atom ring sugars, called septanoses, are increasingly the focus of scientific inquiries because of their potential biological activities. This article details the synthesis, conformational analysis, and protein-binding properties of septanose carbohydrates. A distinction is drawn between septanoses that are substituted in the 6-position of the ring and those that are not. When a C-6 substituent is absent, the structure is essentially that of an aldohexose in its septanose, rather than furanose or pyranose, ring form; they may play as-of-yet unexplored roles in glycobiology. Septanoses having a hydroxymethyl group at C-6, on the other hand, are ring-expanded analogues of pyranoses. Syntheses have moved beyond the preparation of seven-membered ring monosaccharides to the development of septanosyl donors. These donors have been used in the synthesis of novel di- and trisaccharides that contain septanoses as well as a variety of glycoconjugates. Low-energy conformations adopted by septanoses have been organized based on ring substitution and stereochemistry. Instances where septanoses have been demonstrated to bind to natural proteins are presented and analyzed. The major conclusion drawn in the chapter is that advances in the synthesis of septanose carbohydrates now enable a detailed investigation of their activity in a number of biological contexts.
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Islam SM, Richards MR, Taha HA, Byrns SC, Lowary TL, Roy PN. Conformational Analysis of Oligoarabinofuranosides: Overcoming Torsional Barriers with Umbrella Sampling. J Chem Theory Comput 2011; 7:2989-3000. [DOI: 10.1021/ct200333p] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Shahidul M. Islam
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1
| | - Michele R. Richards
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, University of Alberta, Edmonton, AB, Canada T6G 2G2
| | - Hashem A. Taha
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, University of Alberta, Edmonton, AB, Canada T6G 2G2
| | - Simon C. Byrns
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, University of Alberta, Edmonton, AB, Canada T6G 2G2
| | - Todd L. Lowary
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, University of Alberta, Edmonton, AB, Canada T6G 2G2
| | - Pierre-Nicholas Roy
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1
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Kumari M, Balaji PV, Sunoj RB. Quantification of binding affinities of essential sugars with a tryptophan analogue and the ubiquitous role of C-H···π interactions. Phys Chem Chem Phys 2011; 13:6517-30. [PMID: 21369604 DOI: 10.1039/c0cp02559c] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The role of noncovalent interactions in carbohydrate recognition by aromatic amino acids has long been reported. To develop a molecular understanding of noncovalent interactions in the recognition process, we have examined a series of binary complexes between 3-methylindole (3-MeIn) and sugars. In particular, the geometries and binding affinities of 3-MeIn with α/β-D-glucose, β-D-galactose, α-D-mannose and α/β-L-fucose are obtained using the MP2(full)/6-31G(d,p) and the M06/TZV2D//MP2/6-31G(d,p) level of theories. The conventional hydrogen bonding such as N-H···O and C-H···O as well as nonconventional O-H···π and C-H···π type of interactions is, in general, identified as responsible for the moderately strong interaction energies. Large variations in the position-orientations of 3-MeIn with respect to saccharide are noticed, within the same sugar family, as well as across different sugar series. Furthermore, complexes with large differences in their geometries are recognized as capable of exhibiting very similar interaction energies, underscoring the significance of exhaustive conformation sampling, as carried out in the present study. These observations are readily attributed to the differences in the efficiency of the type of interactions enlisted above. The highest and lowest interaction energies, upon inclusion of 50% BSSE correction, are found to be -16.02 and -6.22 kcal mol(-1), respectively, for α-D-glucose (1a) and α-L-fucose (5j). While more number of prominent conventional hydrogen bonding contacts remains as a characteristic feature of the strongly bound complexes, the lower end of the interaction energy spectrum is dominated by multiple C-H···π interactions. The complexes exhibiting as many as four C-H···π contacts are identified in the case of α/β-D-glucose, β-D-galactose, and α/β-L-fucose with an interaction energy hovering around -8 kcal mol(-1). The presence of effective C-H···π interactions is found to be dependent on the saccharide configuration as well as the area of the apolar patch constituted by the C-H groups. The study offers a comprehensive set of binary complexes, across different saccharides, which serves as an illustration of the significance and ubiquitous nature of C-H···π interactions in carbohydrate binding in saccharide-protein complexes.
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Affiliation(s)
- Manju Kumari
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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12
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Garcia L, Maisonneuve S, Xie J, Guillot R, Dorlet P, Rivière E, Desmadril M, Lambert F, Policar C. Sugars to control ligand shape in metal complexes: conformationally constrained glycoligands with a predetermination of stereochemistry and a structural control. Inorg Chem 2010; 49:7282-8. [PMID: 20690737 DOI: 10.1021/ic1002379] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
In coordination chemistry, ligand shape can be used to tune properties, such as metal selectivity, coordination number, electronic structure, redox potential, and metal center stereochemistry including coordination helicates formation, and also to generate cavities for encapsulation. The results presented in this article indicate that two epimeric glycoligands (3 and 4) based on the conformationally restrained xylo- and ribo-1,2-O-isopropylidenefurano scaffolds are preorganized in water through pi-pi stacking due to hydrophobic interactions, as evidenced from excimer observation. The structure obtained in the solid state for one of the Cu(II) complexes (5) is chiral, with an original helical chirality arising from the coiling of the two ligands around the Cu-Cu axis. It shows an unusual double-deck type structure, with pi-pi interaction between two triazoyl-pyridyl rings and with a small cavity between the two Cu(II) ions able to host a bridging water molecule, as suggested by electron paramagnetic resonance. The Cu(II) complex from the epimeric ligand (6) shows similar properties with a mirror-image CD spectrum in the d-d region of the Cu(II). There is a predetermination of chirality at the metal center by the glycoligand induced by the C3 configuration, 6 and 5 being pseudoenantiomers. Interestingly, the stereochemistry at the metal center is here controlled by the combination of pi-stacking and chiral backbone.
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Affiliation(s)
- Ludivine Garcia
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Sud 11, F-91405 Orsay Cedex, France
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Rhoad JS, Cagg BA, Carver PW. Scanning the Potential Energy Surface of Furanosyl Oxocarbenium Ions: Models for Reactive Intermediates in Glycosylation Reactions. J Phys Chem A 2010; 114:5180-6. [DOI: 10.1021/jp9100448] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Jonathan S. Rhoad
- Department of Chemistry, Missouri Western State University, 4525 Downs Drive, St. Joseph, Missouri 64507
| | - Brett A. Cagg
- Department of Chemistry, Missouri Western State University, 4525 Downs Drive, St. Joseph, Missouri 64507
| | - Patrick W. Carver
- Department of Chemistry, Missouri Western State University, 4525 Downs Drive, St. Joseph, Missouri 64507
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14
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Taha HA, Castillo N, Sears DN, Wasylishen RE, Lowary TL, Roy PN. Conformational Analysis of Arabinofuranosides: Prediction of 3JH,H Using MD Simulations with DFT-Derived Spin−Spin Coupling Profiles. J Chem Theory Comput 2009; 6:212-22. [DOI: 10.1021/ct900477x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Hashem A. Taha
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1
| | - Norberto Castillo
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1
| | - Devin N. Sears
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1
| | - Roderick E. Wasylishen
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1
| | - Todd L. Lowary
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1
| | - Pierre-Nicholas Roy
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1
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15
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Peltier P, Euzen R, Daniellou R, Nugier-Chauvin C, Ferrières V. Recent knowledge and innovations related to hexofuranosides: structure, synthesis and applications. Carbohydr Res 2008; 343:1897-923. [DOI: 10.1016/j.carres.2008.02.010] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Revised: 02/08/2008] [Accepted: 02/12/2008] [Indexed: 10/22/2022]
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Abstract
Continuum mean-field models that have been carefully designed to address the various electrostatic and nonelectrostatic interactions that develop between a molecule and a surrounding medium are particularly efficient tools for studying the effects of condensed phases on molecular structure, energetics, properties, spectra, interaction potentials, and dynamics. The SM8 model may be combined with density functional theory or Hartree-Fock theory to describe a solute's electronic structure and its self-consistent-field polarization by a solvent. A key feature is the use of class IV charge models to obtain accurate charge distributions (either in the vapor phase or in solution), even when using small basis sets that are affordable for large systems. A second key feature is that nonelectrostatic effects due to cavity formation, dispersion interactions, and changes in solvent structure are included in terms of empirical atomic surface tensions that depend on geometry but do not require atom-type assignments by the user. Use of an analytic surface area algorithm provides very stable energy gradients that allow geometry optimization in solution. The SM8 continuum model, the culmination of a series of SMx models (x = 1-8), permits the modeling of such diverse media as aqueous and organic solvents, soils, lipid bilayers, and air-water interfaces. In addition to predicting accurate transfer free energies between gaseous and condensed phases or between two different condensed phases, SMx models have been useful for predicting the significant influence of condensed phases on processes associated with a change in molecular charge, including acid/base equilibria and oxidation/reduction processes. In this Account, we provide an overview of the algorithms associated with the computation of free energies of solvation in the SM8 model. We also compare the accuracies of the SM8 model with those of other continuum solvation models. Finally, we highlight applications of the SM8 models to compute ionic solvation free energies, oxidation and reduction potentials, and pK(a) values.
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Affiliation(s)
- Christopher J. Cramer
- Department of Chemistry and Supercomputer Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455
| | - Donald G. Truhlar
- Department of Chemistry and Supercomputer Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455
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17
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Cisnetti F, Guillot R, Thérisod M, Desmadril M, Policar C. Stereocontrol by a Pair of Epimeric Sugar-Derived Ligands of the Coordination Sphere of Copper(II) Complexes. Inorg Chem 2008; 47:2243-5. [DOI: 10.1021/ic702209g] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Federico Cisnetti
- Institut de Chimie Moléculaire et des Matériaux d’Orsay (UMR CNRS 8182) and Institut de Biochimie et Biophysique Moléculaire et Cellulaire (UMR CNRS 8619), Université Paris-Sud 11, 91405 Orsay Cedex, France
| | - Régis Guillot
- Institut de Chimie Moléculaire et des Matériaux d’Orsay (UMR CNRS 8182) and Institut de Biochimie et Biophysique Moléculaire et Cellulaire (UMR CNRS 8619), Université Paris-Sud 11, 91405 Orsay Cedex, France
| | - Michel Thérisod
- Institut de Chimie Moléculaire et des Matériaux d’Orsay (UMR CNRS 8182) and Institut de Biochimie et Biophysique Moléculaire et Cellulaire (UMR CNRS 8619), Université Paris-Sud 11, 91405 Orsay Cedex, France
| | - Michel Desmadril
- Institut de Chimie Moléculaire et des Matériaux d’Orsay (UMR CNRS 8182) and Institut de Biochimie et Biophysique Moléculaire et Cellulaire (UMR CNRS 8619), Université Paris-Sud 11, 91405 Orsay Cedex, France
| | - Clotilde Policar
- Institut de Chimie Moléculaire et des Matériaux d’Orsay (UMR CNRS 8182) and Institut de Biochimie et Biophysique Moléculaire et Cellulaire (UMR CNRS 8619), Université Paris-Sud 11, 91405 Orsay Cedex, France
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18
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Seo M, Castillo N, Ganzynkowicz R, Daniels CR, Woods RJ, Lowary TL, Roy PN. Approach for the Simulation and Modeling of Flexible Rings: Application to the α-D-Arabinofuranoside Ring, a Key Constituent of Polysaccharides from Mycobacterium tuberculosis.. J Chem Theory Comput 2008; 4:184-191. [PMID: 25339852 PMCID: PMC4203666 DOI: 10.1021/ct700284r] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A number of lower organisms (bacteria, fungi, and parasites) produce glycoconjugates that contain furanose rings. Of particular interest to our group are cell wall polysaccharides from mycobacteria, including the human pathogen, Mycobacterium tuberculosis, which contain a large number of arabinofuranose resides. As part of a larger project on the conformational analysis of these molecules, we report here molecular dynamics simulations on methyl α-D-arabinofuranoside (1) using the AMBER force field and the GLYCAM carbohydrate parameter set. We initially studied the ability of this method to predict rotamer populations about the hydroxymethyl group (C4-C5) bond. Importantly, we show that simulation times of up to 200 ns are required in order to obtain convergence of the rotamer populations for this ring system. We also propose a new charge derivation approach that accounts for the flexibility of the furanoside ring by taking an average of the charges from a large number of conformers across the psuedorotational itinerary. The approach yields rotamer populations that are in good agreement with available NMR data and, in addition, provides insight into the nature of the puckering angle and amplitude in 1.
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19
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Mejía SM, Espinal JF, Restrepo A, Mondragón F. Molecular Interaction of (Ethanol)2−Water Heterotrimers. J Phys Chem A 2007; 111:8250-6. [PMID: 17665885 DOI: 10.1021/jp073168g] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The potential energy surface of the (ethanol)2-water heterotrimers for the trans and gauche conformers of ethanol was studied using density functional theory. The same approximation was used for characterizing representative clusters of (ethanol)3, (methanol)3, and (methanol)2-water. Trimerization energies and enthalpies as well as the analysis of geometric parameters suggest that the structures with a cyclic pattern in the three hydrogen bonds of the type O-H---O (primary hydrogen bonds), where all molecules are proton donor-acceptor at the same time, are more stable than those with just two primary hydrogen bonds. Additionally, we propose the formation of "secondary hydrogen bonds" between hydrogen atoms of the methyl group of ethanol and the oxygen atom of water or other ethanol molecule (C-H---O), which were found to be weaker than the primary hydrogen bonds.
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Affiliation(s)
- Sol M Mejía
- Institute of Chemistry, University of Antioquia, A. A. 1226, Medellín, Colombia
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20
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DeMatteo MP, Mei S, Fenton R, Morton M, Baldisseri DM, Hadad CM, Peczuh MW. Conformational analysis of methyl 5-O-methyl septanosides: effect of glycosylation on conformer populations. Carbohydr Res 2006; 341:2927-45. [PMID: 17056019 DOI: 10.1016/j.carres.2006.09.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 09/15/2006] [Accepted: 09/28/2006] [Indexed: 11/26/2022]
Abstract
Methyl 5-O-methyl-alpha-d-glycero-d-idoseptanoside (3) and methyl 5-O-methyl-beta-d-glycero-d-guloseptanoside (4) were investigated as (1-->5)-linked di-/oligoseptanoside mimetics. Here we report the synthesis of 3 and 4 and describe their preferred solution conformations through a combination of ab initio/DFT calculations and (1)H (3)J(H,H) NMR coupling constant analysis. The conformations of 3 and 4 observed in this study are discussed in comparison to those of the parent (C5 hydroxy) compounds 1 and 2. The results indicate that methyl 5-O-methyl-alpha-septanoside 3 is relatively rigid and adopts the same (3,4)TC(5,6) conformation as 1. Methyl 5-O-methyl-beta-septanoside 4 is somewhat less rigid than its parent septanoside (2). In addition to the (6,O)TC(4,5) conformation adopted by 2, beta-septanoside 4 also populates the adjacent (3,4)TC(5,6) conformation. Glycosylation at C5 on beta-septanoside 4 therefore increases its overall flexibility and allows access to alternative ring conformations.
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Affiliation(s)
- Matthew P DeMatteo
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
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21
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Sawada T, Hashimoto T, Nakano H, Shigematsu M, Ishida H, Kiso M. Conformational Study of α‐N‐Acetyl‐D‐Neuraminic Acid by Density Functional Theory. J Carbohydr Chem 2006. [DOI: 10.1080/07328300600778801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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22
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Suzuki T, Kawashima H, Kotoku H, Sota T. Structural Fluctuation and Dynamics of Ribose Puckering in Aqueous Solution from First Principles. J Phys Chem B 2005; 109:12997-3005. [PMID: 16852613 DOI: 10.1021/jp050475i] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Using the method of ab initio molecular dynamics, we examine the structural fluctuation and the low-frequency dynamics of beta-ribofuranose puckering in aqueous solution. Our analysis suggests that the distance between the anomeric and hydroxymethyl oxygens is a simple relevant geometrical parameter that dynamically correlates with the phase angle in the north region. The time-frequency analysis using the Hilbert-Huang transform also confirms the correlation, and most of the instantaneous frequencies for the phase angle and the above distance are found to be concentrated on the region below about 100 cm(-1). Our analysis of ab initio molecular dynamics trajectories suggests that the molecular origin of the hydration effects on the low-frequency dynamics of beta-ribofuranose puckering is closely related to this correlation and thus primarily attributed to the relatively local interactions among the anomeric and hydroxymethyl oxygens and the surrounding water molecules near them. Additionally, we discuss the difference in the low-frequency dynamics of beta-ribofuranose puckering between two hydroxymethyl rotamers.
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Affiliation(s)
- Teppei Suzuki
- Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan.
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23
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Suzuki T, Sota T. Circular Hydrogen Bond Networks on the Surface of β-Ribofuranose in Aqueous Solution. J Phys Chem B 2005; 109:12603-11. [PMID: 16852559 DOI: 10.1021/jp050100x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This paper examines the hydration structure on the surface of beta-ribofuranose in aqueous solution, using the ab initio molecular dynamics method. In particular, we focus on circular hydrogen bond networks involving two ribofuranose oxygens and three water molecules. In our simulations, the circular hydrogen bond networks near the ring oxygen of beta-ribofuranose are found to be significantly influenced by the orientation of the hydroxymethyl group. The arrangements of hydrogen bonds observed in the circular hydrogen bond networks are both homodromic and antidromic. To explain these observations, we analyze the electronic properties of the first-hydration-shell water molecules and the OH groups of beta-ribofuranose, using the centers of their maximally localized Wannier functions. The dipole moments of the proton-accepting first-hydration-shell water molecules in our well-defined circular hydrogen bond networks are found to increase by about 0.3 D compared with that of liquid water, indicating the relatively strong polarization effects created by the interactions between the OH groups of the solute and the surrounding water molecules. Our analysis also implies that circular H-bond networks cannot be fully explained from a simple geometrical point of view.
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Affiliation(s)
- Teppei Suzuki
- Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan.
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24
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Thibaudeau C, Stenutz R, Hertz B, Klepach T, Zhao S, Wu Q, Carmichael I, Serianni AS. Correlated C-C and C-O bond conformations in saccharide hydroxymethyl groups: parametrization and application of redundant 1H-1H, 13C-1H, and 13C-13C NMR J-couplings. J Am Chem Soc 2005; 126:15668-85. [PMID: 15571389 DOI: 10.1021/ja0306718] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Methyl alpha- and beta-pyranosides of d-glucose and d-galactose 1-4 were prepared containing single sites of (13)C-enrichment at C4, C5, and C6 (12 compounds), and (1)H and (13)C[(1)H] NMR spectra were obtained to determine a complete set of J-couplings ((1)J, (2)J, and (3)J) involving the labeled carbon and nearby protons and carbons within the exocyclic hydroxymethyl group (CH(2)OH) of each compound. In parallel theoretical studies, the dependencies of (1)J, (2)J, and (3)J involving (1)H and (13)C on the C5-C6 (omega) and C6-O6 (theta;) torsion angles in aldohexopyranoside model compounds were computed using density functional theory (DFT) and a special basis set designed to reliably recover the Fermi contact contribution to the coupling. Complete hypersurfaces for (1)J(C5,C6), (2)J(C5,H6)(R), (2)J(C5,H6)(S), (2)J(C6,H5), (2)J(C4,C6), (3)J(C4,H6)(R), (3)J(C4,H6)(S), and (3)J(C6,H4), as well as (2)J(H6)(R)(,H6)(S), (3)J(H5,H6)(R), and (3)J(H5,H6)(S), were obtained and used to parametrize new equations correlating these couplings to omega and/or theta;. DFT-computed couplings were also tested for accuracy by measuring J-couplings in (13)C-labeled 4,6-O-ethylidene derivatives of d-glucose and d-galactose in which values of omega and theta; were constrained. Using a new computer program, Chymesa, designed to utilize multiple J-couplings sensitive to exocyclic CH(2)OH conformation, the ensemble of experimental couplings observed in 1-4 were analyzed to yield preferred rotamer populations about omega and theta;. Importantly, due to the sensitivity of some couplings, most notably (2)J(H6)(R)(,H6)(S), (2)J(C5,H6)(R), and (2)J(C5,H6)(S), to both omega and theta;, unique information on correlated conformation about both torsion angles was obtained. The latter treatment represents a means of evaluating correlated conformation in 1,6-linked oligosaccharides, since psi and theta; are redundant in these linkages. In the latter regard, multiple, redundant scalar couplings originating from both sides of the glycosidic linkage can be used collectively to evaluate conformational correlations between psi/theta; and C5-C6 bond rotamers.
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Affiliation(s)
- Christophe Thibaudeau
- Department of Chemistry and Biochemistry and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA
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25
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Cociorva OM, Gurcha SS, Besra GS, Lowary TL. Oligosaccharides as inhibitors of mycobacterial arabinosyltransferases. Di- and trisaccharides containing C-3 modified arabinofuranosyl residues. Bioorg Med Chem 2005; 13:1369-79. [PMID: 15670944 DOI: 10.1016/j.bmc.2004.11.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Revised: 10/29/2004] [Accepted: 11/04/2004] [Indexed: 11/20/2022]
Abstract
The assembly of the arabinan portions of cell wall polysaccharides in mycobacteria involves a family of arabinosyltransferases (AraT's) that promote the polymerization of decaprenolphosphoarabinose. Mycobacterial viability depends upon the ability of the organism to synthesize an intact arabinan and thus compounds that inhibit these AraT's are both useful biochemical tools as well as potential lead compounds for new anti-tuberculosis agents. We describe here the preparation of oligosaccharide fragments of mycobacterial arabinan that contain arabinofuranosyl residues modified at C-3 by the replacement of the hydroxyl group with an amino, azido or methoxy functionality. Subsequent testing of these oligosaccharides as inhibitors of mycobacterial AraT's revealed that all inhibited the enzymes, but to varying degrees. In further studies, each compound was shown to have only low activity as an inhibitor of mycobacterial growth.
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Affiliation(s)
- Oana M Cociorva
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
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26
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Dematteo MP, Snyder NL, Morton M, Baldisseri DM, Hadad CM, Peczuh MW. Septanose Carbohydrates: Synthesis and Conformational Studies of Methyl α-d-glycero-d-Idoseptanoside and Methyl β-d-glycero-d-Guloseptanoside. J Org Chem 2004; 70:24-38. [PMID: 15624903 DOI: 10.1021/jo048932z] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We report the synthesis of methyl alpha-D-glycero-D-idoseptanoside (1) and methyl beta-D-glycero-D-guloseptanoside (2) and the characterization of their preferred solution conformations by computational chemistry and (1)H NMR (3)J(H,H) coupling constant analysis. Central to the synthetic approach was the epoxidation of glucose-derived oxepine 3 using DMDO. Nucleophilic attack on the resulting 1,2-anhydroseptanose using NaOCH(3) in CH(3)OH followed by deprotection provided the 1,2-trans diastereomers 1 and 2. The computational approach for determining the preferred low energy septanose conformations began with a pseudo Monte Carlo search for each isomer using minimization with the AMBER force field. Single-point energy calculations (HF/6-31G *and B3LYP/6-31+G**) as well as full geometry optimizations in a model for aqueous solvent were then conducted using the conformers within 5 kcal/mol of the AMBER global minimum. Calculated (3)J(H,H) values, based on a Boltzmann distribution of the computed low energy conformers, were compared to experimental (3)J(H,H) values from (1)H NMR coupling constant analyses. The correlation between calculated and observed values suggest that septanose carbohydrates are not so flexible and should generally prefer one twist-chair (TC) conformation.
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Affiliation(s)
- Matthew P Dematteo
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA
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27
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Fragoso-Serrano M, Guillén-Jaramillo G, Pereda-Miranda R, Cerda-García-Rojas CM. Conformational analysis of sulfur-containing 6-deoxy-l-hexose derivatives by molecular modeling and NMR spectroscopy. A theoretical study and experimental evidence of intramolecular nonbonded interactions between sulfur and oxygen. J Org Chem 2003; 68:7167-75. [PMID: 12968866 DOI: 10.1021/jo034492k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
6-Deoxy-l-mannose diphenyldithioacetal (1) unexpectedly gave the rearranged products phenyl 3,4-di-O-acetyl-2-S-phenyl-1,2-dithio-6-deoxy-beta-l-glucopyranoside (9) and 3,4-di-O-acetyl-2,5-anhydro-6-deoxy-l-glucose diphenyldithioacetal (10) upon treatment with acetyl chloride, while 6-deoxy-l-mannose ethylenedithioacetal (3) yielded (4aR,6S,7S,8R,8aS)-7,8-diacetyloxy-6-methylhexahydro-4aH-[1,4]dithiino[2,3b]pyran (11), whose structure was further confirmed by X-ray diffraction, and 3,4-di-O-acetyl-2,5-anhydro-l-rhamnose ethylenedithioacetal (12). The geometry of the four rearranged products as well as that of 1-thio-6-deoxy-l-mannopyranosides 5 and 7 and their acetyl derivatives 6 and 8 was studied by density functional theory (B3LYP/6-31G) molecular models, in combination with a Karplus-type analysis of the NMR vicinal coupling constants, revealing that the six-membered ring of pyranosides 5-9 and 11 exists in a slightly distorted chair conformation (6-13% distortion) and that the conformational behavior of the 2,5-anhydro-6-deoxy-l-glucose dithioacetals 10 and 12 is strongly influenced by the presence of stabilizing intramolecular nonbonded sulfur-oxygen 1,4- and 1,5-interactions. Compounds 9-12 were formed by a molecular rearrangement via sulfonium ion intermediates followed by stereoselective intramolecular cyclizations as formulated by the quantum chemical calculations performed in the present study.
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Affiliation(s)
- Mabel Fragoso-Serrano
- Departamento de Química, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado 14-740, Mexico City 07000, Mexico
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28
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Houseknecht JB, Lowary TL, Hadad CM. Gas- and Solution-Phase Energetics of the Methyl α- and β-d-Aldopentofuranosides. J Phys Chem A 2003. [DOI: 10.1021/jp027716w] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
| | - Todd L. Lowary
- Department of Chemistry, The Ohio State University, Columbus, Ohio 43210
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29
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Houseknecht JB, Lowary TL, Hadad CM. Improved Karplus Equations for3JC1,H4in Aldopentofuranosides: Application to the Conformational Preferences of the Methyl Aldopentofuranosides. J Phys Chem A 2003. [DOI: 10.1021/jp026610y] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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30
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Akdaǧ A, Carver CM, McKee ML, Schneller SW. Theoretical Study of 9-β- d-Erythrofuranosyladenine and Corresponding Carbocyclic Analogues. Evidence for a Base-Activated Conformational Lock. J Phys Chem A 2002. [DOI: 10.1021/jp021563v] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Akin Akdaǧ
- Department of Chemistry, Auburn University, Auburn, Alabama 36849
| | | | - Michael L. McKee
- Department of Chemistry, Auburn University, Auburn, Alabama 36849
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31
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Houseknecht JB, Altona C, Hadad CM, Lowary TL. Conformational analysis of furanose rings with PSEUROT: parametrization for rings possessing the arabino, lyxo, ribo, and xylo stereochemistry and application to arabinofuranosides. J Org Chem 2002; 67:4647-51. [PMID: 12098271 DOI: 10.1021/jo025635q] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The solution conformation of a furanose ring can be assessed through PSEUROT analysis of three-bond (1)H-(1)H coupling constants ((3)J(HH)) of the ring hydrogens. For each coupling constant, PSEUROT requires two parameters, A and B, which are used to translate the H[bond]C[bond]C[bond]H dihedral angle predicted from the (3)J(HH) into an endocyclic torsion angle from which the identity of the conformers can be determined. In this paper, we have used density functional theory methods to generate a family of envelope conformers for methyl furanosides 1-8. From these structures, A and B were calculated for each H[bond]C[bond]C[bond]H fragment. In turn, the values of these parameters for the arabinofuranose ring were used in PSEUROT calculations to determine the conformers populated by monosaccharides 1 and 2 as well as the furanose rings in oligosaccharides 9-15. The results of these analyses are consistent with the low-energy conformers identified from previous computational and X-ray crystallographic studies of 1 and 2.
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Affiliation(s)
- Justin B Houseknecht
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA
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32
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Guler LP, Yu YQ, Kenttämaa HI. An Experimental and Computational Study of the Gas-Phase Structures of Five-Carbon Monosaccharides. J Phys Chem A 2002. [DOI: 10.1021/jp025577c] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Leonard P. Guler
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393
| | - Ying-Qing Yu
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393
| | - Hilkka I. Kenttämaa
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393
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33
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Callam CS, Lowary TL. Synthesis and conformational investigation of methyl 4a-carba-D-arabinofuranosides. J Org Chem 2001; 66:8961-72. [PMID: 11749629 DOI: 10.1021/jo010827r] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The synthesis of carbasugar analogues of methyl alpha-D-arabinofuranoside and methyl beta-D-arabinofuranoside (3 and 4) is reported. The route developed involves the conversion of D-mannose into a suitably protected diene (13), which is then cyclized via olefin metathesis. The resulting cyclopentene (14) is stereoselectively hydrogenated to provide an intermediate that can be used for the synthesis of both targets. Through the use of NMR spectroscopy, we have probed the ring conformation of 3 and 4, as well as the rotamer populations about the C(4)-C(5) and C(1)-O(1) bonds. These studies have demonstrated that there are differences in ring conformation between these carbasugars and their glycoside parents (1 and 2). However, only minor differences are seen in the rotameric equilibrium about the C(4)-C(5) bond in 3 and 4 relative to 1 and 2. In regard to the C(1)-O(1) bond, NOE data from 3 and 4 suggest that the favored position about this bond is similar to that in the glycosides; that is, the methyl group is anti to C(2). However, confirmation of this preference through measurement of (3)J(C,C) between the methyl group and C(2) or C(4a) was not successful.
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Affiliation(s)
- C S Callam
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
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34
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Callam CS, Singer SJ, Lowary TL, Hadad CM. Computational analysis of the potential energy surfaces of glycerol in the gas and aqueous phases: effects of level of theory, basis set, and solvation on strongly intramolecularly hydrogen-bonded systems. J Am Chem Soc 2001; 123:11743-54. [PMID: 11716731 DOI: 10.1021/ja011785r] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The 126 possible conformations of 1,2,3-propanetriol (glycerol) have been studied by ab initio molecular orbital and density functional theory calculations in the gas and aqueous phases at multiple levels of theory and basis sets. The partial potential energy surface for glycerol as well as an analysis of the conformational properties and hydrogen-bonding trends in both phases have been obtained. In the gas phase at the G2(MP2) and CBS-QB3 levels of theory, the important, low-energy conformers are structures 100 and 95. In the aqueous phase at the SM5.42/HF/6-31G* level of theory, the lowest energy conformers are structures 95 and 46. Boltzmann distributions have been determined from these high-level calculations, and good agreement is observed when these distributions are compared to the available experimental data. These calculations indicate that the enthalpic and entropic contributions to the Gibbs free energy are important for an accurate determination of the conformational and energetic preferences of glycerol. Different levels of theory and basis sets were used in order to understand the effects of nonbonded interactions (i.e., intramolecular hydrogen bonding). The efficiency of basis set and level of theory in dealing with the issue of intramolecular hydrogen bonding and reproducing the correct energetic and geometrical trends is discussed, especially with relevance to practical computational methods for larger polyhydroxylated compounds, such as oligosaccharides.
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Affiliation(s)
- C S Callam
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA
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