Revealing the compact structure of lactic acid bacterial hetero-exopolysaccharides by SAXS and DLS

Sanaullah Khan, Johnny Birch, Pernille Harris, Marie-Rose Van Calsteren, Richard Ipsen, Günther H.J. Peters, Birte Svensson, Kristoffer Almdal

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Molecular structures of exopolysaccharides are required to understand their functions and the relationships between the structure and physical and rheological properties. Small-angle X-ray scattering and dynamic light scattering were used in conjunction with molecular modeling to characterize solution structures of three lactic acid bacterial hetero-exopolysaccharides (HePS-1, HePS-2 and HePS-3). Values of radius of gyration RG, cross-sectional radius of gyration RXS, approximate length L and hydrodynamic diameter were not directly proportional to the molar mass and indicated the HePSs adopted a compact coil-like rather than an extended conformation. Constrained molecular modeling of 15,000 randomised HePS-1 conformers resulted in five best-fit structures with R factor of 3.94.6% revealing random coil-like structure. Φ and Ψ angle analysis of glycosidic linkages in HePS-1 structures suggests Galf residues significantly influence the conformation. Ab initio scattering modeling of HePS-2 and HePS-3 gave excellent curve fittings with χ2 of 0.43 and 0.34 for best-fit models, respectively, compatible with coil-like conformation. The findings disclose solution behaviour of HePS relevant for their interactions with biomacromolecules e.g. milk proteins.
Original languageEnglish
JournalBiomacromolecules
Volume18
Issue number3
Pages (from-to)747-757
ISSN1525-7797
DOIs
Publication statusPublished - 2017

Cite this

@article{cbd361634ed24075ae49d97720a006d3,
title = "Revealing the compact structure of lactic acid bacterial hetero-exopolysaccharides by SAXS and DLS",
abstract = "Molecular structures of exopolysaccharides are required to understand their functions and the relationships between the structure and physical and rheological properties. Small-angle X-ray scattering and dynamic light scattering were used in conjunction with molecular modeling to characterize solution structures of three lactic acid bacterial hetero-exopolysaccharides (HePS-1, HePS-2 and HePS-3). Values of radius of gyration RG, cross-sectional radius of gyration RXS, approximate length L and hydrodynamic diameter were not directly proportional to the molar mass and indicated the HePSs adopted a compact coil-like rather than an extended conformation. Constrained molecular modeling of 15,000 randomised HePS-1 conformers resulted in five best-fit structures with R factor of 3.94.6{\%} revealing random coil-like structure. Φ and Ψ angle analysis of glycosidic linkages in HePS-1 structures suggests Galf residues significantly influence the conformation. Ab initio scattering modeling of HePS-2 and HePS-3 gave excellent curve fittings with χ2 of 0.43 and 0.34 for best-fit models, respectively, compatible with coil-like conformation. The findings disclose solution behaviour of HePS relevant for their interactions with biomacromolecules e.g. milk proteins.",
author = "Sanaullah Khan and Johnny Birch and Pernille Harris and {Van Calsteren}, Marie-Rose and Richard Ipsen and Peters, {G{\"u}nther H.J.} and Birte Svensson and Kristoffer Almdal",
year = "2017",
doi = "10.1021/acs.biomac.6b01597",
language = "English",
volume = "18",
pages = "747--757",
journal = "Biomacromolecules",
issn = "1525-7797",
publisher = "American Chemical Society",
number = "3",

}

Revealing the compact structure of lactic acid bacterial hetero-exopolysaccharides by SAXS and DLS. / Khan, Sanaullah; Birch, Johnny; Harris, Pernille; Van Calsteren, Marie-Rose; Ipsen, Richard; Peters, Günther H.J.; Svensson, Birte; Almdal, Kristoffer.

In: Biomacromolecules, Vol. 18, No. 3, 2017, p. 747-757.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Revealing the compact structure of lactic acid bacterial hetero-exopolysaccharides by SAXS and DLS

AU - Khan, Sanaullah

AU - Birch, Johnny

AU - Harris, Pernille

AU - Van Calsteren, Marie-Rose

AU - Ipsen, Richard

AU - Peters, Günther H.J.

AU - Svensson, Birte

AU - Almdal, Kristoffer

PY - 2017

Y1 - 2017

N2 - Molecular structures of exopolysaccharides are required to understand their functions and the relationships between the structure and physical and rheological properties. Small-angle X-ray scattering and dynamic light scattering were used in conjunction with molecular modeling to characterize solution structures of three lactic acid bacterial hetero-exopolysaccharides (HePS-1, HePS-2 and HePS-3). Values of radius of gyration RG, cross-sectional radius of gyration RXS, approximate length L and hydrodynamic diameter were not directly proportional to the molar mass and indicated the HePSs adopted a compact coil-like rather than an extended conformation. Constrained molecular modeling of 15,000 randomised HePS-1 conformers resulted in five best-fit structures with R factor of 3.94.6% revealing random coil-like structure. Φ and Ψ angle analysis of glycosidic linkages in HePS-1 structures suggests Galf residues significantly influence the conformation. Ab initio scattering modeling of HePS-2 and HePS-3 gave excellent curve fittings with χ2 of 0.43 and 0.34 for best-fit models, respectively, compatible with coil-like conformation. The findings disclose solution behaviour of HePS relevant for their interactions with biomacromolecules e.g. milk proteins.

AB - Molecular structures of exopolysaccharides are required to understand their functions and the relationships between the structure and physical and rheological properties. Small-angle X-ray scattering and dynamic light scattering were used in conjunction with molecular modeling to characterize solution structures of three lactic acid bacterial hetero-exopolysaccharides (HePS-1, HePS-2 and HePS-3). Values of radius of gyration RG, cross-sectional radius of gyration RXS, approximate length L and hydrodynamic diameter were not directly proportional to the molar mass and indicated the HePSs adopted a compact coil-like rather than an extended conformation. Constrained molecular modeling of 15,000 randomised HePS-1 conformers resulted in five best-fit structures with R factor of 3.94.6% revealing random coil-like structure. Φ and Ψ angle analysis of glycosidic linkages in HePS-1 structures suggests Galf residues significantly influence the conformation. Ab initio scattering modeling of HePS-2 and HePS-3 gave excellent curve fittings with χ2 of 0.43 and 0.34 for best-fit models, respectively, compatible with coil-like conformation. The findings disclose solution behaviour of HePS relevant for their interactions with biomacromolecules e.g. milk proteins.

U2 - 10.1021/acs.biomac.6b01597

DO - 10.1021/acs.biomac.6b01597

M3 - Journal article

VL - 18

SP - 747

EP - 757

JO - Biomacromolecules

JF - Biomacromolecules

SN - 1525-7797

IS - 3

ER -