An Unusual Carbohydrate Conformation is Evident in Moraxella catarrhalis Oligosaccharides
Oligosaccharide structures derived from the lipooligosaccharide of M. catarrhalis show that the highly branched glucose-rich inner core of the oligosaccharide has an altered conformation compared to the most truncated tetra-glucose-Kdo lgt1/4Δ oligosaccharide structure. Addition of one residue each...
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| Format: | Article |
| Language: | English |
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MDPI AG
2015-08-01
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| Series: | Molecules |
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| Online Access: | http://www.mdpi.com/1420-3049/20/8/14234 |
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| author | Martin Frank Patrick M. Collins Ian R. Peak I. Darren Grice Jennifer C. Wilson |
| author_facet | Martin Frank Patrick M. Collins Ian R. Peak I. Darren Grice Jennifer C. Wilson |
| author_sort | Martin Frank |
| collection | DOAJ |
| description | Oligosaccharide structures derived from the lipooligosaccharide of M. catarrhalis show that the highly branched glucose-rich inner core of the oligosaccharide has an altered conformation compared to the most truncated tetra-glucose-Kdo lgt1/4Δ oligosaccharide structure. Addition of one residue each to the (1-4) and (1-6) chains to give the lgt2Δ oligosaccharide is the minimum requirement for this conformational change to occur. Extensive molecular modeling and NMR investigations have shown that the (1-3), (1-4), and (1-6) glycosidic linkages from the central α-D-Glcp have significantly altered conformational preferences between the two structures. For the lgt1/4Δ oligosaccharide the (1-3) and (1-4) linkage populates predominantly the syn minimum on the conformational free energy map and for the (1-6) linkage conformational flexibility is observed, which is supported by 1H-NMR T1 measurements. For the lgt2Δ oligosaccharide the unusual “(1-4)anti-ψ(1-6)gg” conformation, which could be confirmed by long-range NOE signals, is a dominant conformation in which the oligosaccharide is very compact with the terminal α-D-GlcNAc residue folding back towards the center of the molecule leading to an extensive intra-molecular hydrophobic interaction between the terminal residues. Comparing effective H-H distances, which were calculated for conformational sub-ensembles, with the NOE distances revealed that typically multiple conformations could be present without significantly violating the measured NOE restraints. For lgt2Δ the presence of more than one conformation is supported by the NOE data. |
| first_indexed | 2024-12-19T23:05:24Z |
| format | Article |
| id | doaj.art-c6fcdc96c84848c5ba900621294e6d4d |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-12-19T23:05:24Z |
| publishDate | 2015-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-c6fcdc96c84848c5ba900621294e6d4d2022-12-21T20:02:24ZengMDPI AGMolecules1420-30492015-08-01208142341425310.3390/molecules200814234molecules200814234An Unusual Carbohydrate Conformation is Evident in Moraxella catarrhalis OligosaccharidesMartin Frank0Patrick M. Collins1Ian R. Peak2I. Darren Grice3Jennifer C. Wilson4Biognos AB, Generatorsgatan 1, 41705 Gothenburg, SwedenInstitute for Glycomics, Gold Coast Campus, Griffith University, 4222 Queensland, AustraliaInstitute for Glycomics and School of Medical Science, Gold Coast Campus, Griffith University, 4222 Queensland, AustraliaInstitute for Glycomics and School of Medical Science, Gold Coast Campus, Griffith University, 4222 Queensland, AustraliaMenzies Health Institute and School of Medical Science, Gold Coast Campus, Griffith University, 4222 Queensland, AustraliaOligosaccharide structures derived from the lipooligosaccharide of M. catarrhalis show that the highly branched glucose-rich inner core of the oligosaccharide has an altered conformation compared to the most truncated tetra-glucose-Kdo lgt1/4Δ oligosaccharide structure. Addition of one residue each to the (1-4) and (1-6) chains to give the lgt2Δ oligosaccharide is the minimum requirement for this conformational change to occur. Extensive molecular modeling and NMR investigations have shown that the (1-3), (1-4), and (1-6) glycosidic linkages from the central α-D-Glcp have significantly altered conformational preferences between the two structures. For the lgt1/4Δ oligosaccharide the (1-3) and (1-4) linkage populates predominantly the syn minimum on the conformational free energy map and for the (1-6) linkage conformational flexibility is observed, which is supported by 1H-NMR T1 measurements. For the lgt2Δ oligosaccharide the unusual “(1-4)anti-ψ(1-6)gg” conformation, which could be confirmed by long-range NOE signals, is a dominant conformation in which the oligosaccharide is very compact with the terminal α-D-GlcNAc residue folding back towards the center of the molecule leading to an extensive intra-molecular hydrophobic interaction between the terminal residues. Comparing effective H-H distances, which were calculated for conformational sub-ensembles, with the NOE distances revealed that typically multiple conformations could be present without significantly violating the measured NOE restraints. For lgt2Δ the presence of more than one conformation is supported by the NOE data.http://www.mdpi.com/1420-3049/20/8/14234carbohydrate conformationsoligosaccharidesmolecular dynamics simulationsNMR |
| spellingShingle | Martin Frank Patrick M. Collins Ian R. Peak I. Darren Grice Jennifer C. Wilson An Unusual Carbohydrate Conformation is Evident in Moraxella catarrhalis Oligosaccharides Molecules carbohydrate conformations oligosaccharides molecular dynamics simulations NMR |
| title | An Unusual Carbohydrate Conformation is Evident in Moraxella catarrhalis Oligosaccharides |
| title_full | An Unusual Carbohydrate Conformation is Evident in Moraxella catarrhalis Oligosaccharides |
| title_fullStr | An Unusual Carbohydrate Conformation is Evident in Moraxella catarrhalis Oligosaccharides |
| title_full_unstemmed | An Unusual Carbohydrate Conformation is Evident in Moraxella catarrhalis Oligosaccharides |
| title_short | An Unusual Carbohydrate Conformation is Evident in Moraxella catarrhalis Oligosaccharides |
| title_sort | unusual carbohydrate conformation is evident in moraxella catarrhalis oligosaccharides |
| topic | carbohydrate conformations oligosaccharides molecular dynamics simulations NMR |
| url | http://www.mdpi.com/1420-3049/20/8/14234 |
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