Substrate preference of an ABC importer corresponds to selective growth on β-(1,6)-galactosides in Bifidobacterium animalis subsp. lactis

Mia Christine Theilmann, Folmer Fredslund, Birte Svensson, Leila Lo Leggio, Maher Abou Hachem*

*Corresponding author for this work

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Abstract

Bifidobacteria are exposed to substantial amounts of dietary β-galactosides. Distinctive preferences for growth on different β-galactosides are observed within Bifidobacterium members, but the basis of these preferences remains unclear. We previously described the first β-(1,6)/(1,3)-galactosidase from Bifidobacterium animalis subsp. lactis Bl-04. This enzyme is relatively promiscuous, exhibiting only 5-fold higher efficiency on the preferred β-(1,6)-galactobiose than the β-(1,4) isomer. Here, we characterize the solute-binding protein (Bal6GBP) that governs the specificity of the ABC transporter encoded by the same β-galactoside-utilization locus. We observed that although Bal6GBP recognizes both β-(1,6)- and β-(1,4)-galactobiose, Bal6GBP has a 1630-fold higher selectivity for the former, reflected in dramatic differences in growth, with several hours lag on less preferred β-(1,4)- and β-(1,3)-galactobiose. Experiments performed in the presence of varying proportions of β-(1,4)/ β-(1,6)-galactobioses indicated that the preferred substrate was preferentially depleted from the culture supernatant. This established that the poor growth on the non-preferred β-(1,4) was due to inefficient uptake. We solved the structure of Bal6GBP in complex with β-(1,6)-galactobiose at 1.39 Å resolution, revealing the structural basis of this strict selectivity. Moreover, we observed a close evolutionary relationship with the human milk disaccharide lacto-N-biose-binding protein from Bifidobacterium longum, indicating that the recognition of the non-reducing galactosyl is essentially conserved, whereas the adjacent position is diversified to fit different glycosidic linkages and monosaccharide residues. These findings indicate that oligosaccharide uptake has a pivotal role in governing selectivity for distinct growth substrates and have uncovered evolutionary trajectories that shape the diversification of sugar-uptake proteins within Bifidobacterium.
Original languageEnglish
JournalJournal of Biological Chemistry
Volume294
Issue number31
Pages (from-to)11701-11711
Number of pages12
ISSN0021-9258
DOIs
Publication statusPublished - 2019

Keywords

  • ABC transport
  • Actinobacteria
  • Bifidobacteria
  • Crystal structure
  • Enzyme kinetics
  • Galactoogliosaccharides (GOS)
  • Human milk ogliosaccharides (HMO)
  • Human gut microbiota
  • Isothermal titration calorimetry (ITC)
  • Microbiome
  • Prebitoic
  • Probiotic
  • Protein evolution
  • Surface plasmon resonance (SPR)

Cite this

@article{fa61a3bba750480894788b4f09f1a76d,
title = "Substrate preference of an ABC importer corresponds to selective growth on β-(1,6)-galactosides in Bifidobacterium animalis subsp. lactis",
abstract = "Bifidobacteria are exposed to substantial amounts of dietary β-galactosides. Distinctive preferences for growth on different β-galactosides are observed within Bifidobacterium members, but the basis of these preferences remains unclear. We previously described the first β-(1,6)/(1,3)-galactosidase from Bifidobacterium animalis subsp. lactis Bl-04. This enzyme is relatively promiscuous, exhibiting only 5-fold higher efficiency on the preferred β-(1,6)-galactobiose than the β-(1,4) isomer. Here, we characterize the solute-binding protein (Bal6GBP) that governs the specificity of the ABC transporter encoded by the same β-galactoside-utilization locus. We observed that although Bal6GBP recognizes both β-(1,6)- and β-(1,4)-galactobiose, Bal6GBP has a 1630-fold higher selectivity for the former, reflected in dramatic differences in growth, with several hours lag on less preferred β-(1,4)- and β-(1,3)-galactobiose. Experiments performed in the presence of varying proportions of β-(1,4)/ β-(1,6)-galactobioses indicated that the preferred substrate was preferentially depleted from the culture supernatant. This established that the poor growth on the non-preferred β-(1,4) was due to inefficient uptake. We solved the structure of Bal6GBP in complex with β-(1,6)-galactobiose at 1.39 {\AA} resolution, revealing the structural basis of this strict selectivity. Moreover, we observed a close evolutionary relationship with the human milk disaccharide lacto-N-biose-binding protein from Bifidobacterium longum, indicating that the recognition of the non-reducing galactosyl is essentially conserved, whereas the adjacent position is diversified to fit different glycosidic linkages and monosaccharide residues. These findings indicate that oligosaccharide uptake has a pivotal role in governing selectivity for distinct growth substrates and have uncovered evolutionary trajectories that shape the diversification of sugar-uptake proteins within Bifidobacterium.",
keywords = "ABC transport, Actinobacteria, Bifidobacteria, Crystal structure, Enzyme kinetics, Galactoogliosaccharides (GOS), Human milk ogliosaccharides (HMO), Human gut microbiota, Isothermal titration calorimetry (ITC), Microbiome, Prebitoic, Probiotic, Protein evolution, Surface plasmon resonance (SPR)",
author = "Theilmann, {Mia Christine} and Folmer Fredslund and Birte Svensson and {Lo Leggio}, Leila and {Abou Hachem}, Maher",
year = "2019",
doi = "10.1074/jbc.RA119.008843",
language = "English",
volume = "294",
pages = "11701--11711",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology, Inc.",
number = "31",

}

Substrate preference of an ABC importer corresponds to selective growth on β-(1,6)-galactosides in Bifidobacterium animalis subsp. lactis. / Theilmann, Mia Christine; Fredslund, Folmer; Svensson, Birte; Lo Leggio, Leila; Abou Hachem, Maher .

In: Journal of Biological Chemistry, Vol. 294, No. 31, 2019, p. 11701-11711.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Substrate preference of an ABC importer corresponds to selective growth on β-(1,6)-galactosides in Bifidobacterium animalis subsp. lactis

AU - Theilmann, Mia Christine

AU - Fredslund, Folmer

AU - Svensson, Birte

AU - Lo Leggio, Leila

AU - Abou Hachem, Maher

PY - 2019

Y1 - 2019

N2 - Bifidobacteria are exposed to substantial amounts of dietary β-galactosides. Distinctive preferences for growth on different β-galactosides are observed within Bifidobacterium members, but the basis of these preferences remains unclear. We previously described the first β-(1,6)/(1,3)-galactosidase from Bifidobacterium animalis subsp. lactis Bl-04. This enzyme is relatively promiscuous, exhibiting only 5-fold higher efficiency on the preferred β-(1,6)-galactobiose than the β-(1,4) isomer. Here, we characterize the solute-binding protein (Bal6GBP) that governs the specificity of the ABC transporter encoded by the same β-galactoside-utilization locus. We observed that although Bal6GBP recognizes both β-(1,6)- and β-(1,4)-galactobiose, Bal6GBP has a 1630-fold higher selectivity for the former, reflected in dramatic differences in growth, with several hours lag on less preferred β-(1,4)- and β-(1,3)-galactobiose. Experiments performed in the presence of varying proportions of β-(1,4)/ β-(1,6)-galactobioses indicated that the preferred substrate was preferentially depleted from the culture supernatant. This established that the poor growth on the non-preferred β-(1,4) was due to inefficient uptake. We solved the structure of Bal6GBP in complex with β-(1,6)-galactobiose at 1.39 Å resolution, revealing the structural basis of this strict selectivity. Moreover, we observed a close evolutionary relationship with the human milk disaccharide lacto-N-biose-binding protein from Bifidobacterium longum, indicating that the recognition of the non-reducing galactosyl is essentially conserved, whereas the adjacent position is diversified to fit different glycosidic linkages and monosaccharide residues. These findings indicate that oligosaccharide uptake has a pivotal role in governing selectivity for distinct growth substrates and have uncovered evolutionary trajectories that shape the diversification of sugar-uptake proteins within Bifidobacterium.

AB - Bifidobacteria are exposed to substantial amounts of dietary β-galactosides. Distinctive preferences for growth on different β-galactosides are observed within Bifidobacterium members, but the basis of these preferences remains unclear. We previously described the first β-(1,6)/(1,3)-galactosidase from Bifidobacterium animalis subsp. lactis Bl-04. This enzyme is relatively promiscuous, exhibiting only 5-fold higher efficiency on the preferred β-(1,6)-galactobiose than the β-(1,4) isomer. Here, we characterize the solute-binding protein (Bal6GBP) that governs the specificity of the ABC transporter encoded by the same β-galactoside-utilization locus. We observed that although Bal6GBP recognizes both β-(1,6)- and β-(1,4)-galactobiose, Bal6GBP has a 1630-fold higher selectivity for the former, reflected in dramatic differences in growth, with several hours lag on less preferred β-(1,4)- and β-(1,3)-galactobiose. Experiments performed in the presence of varying proportions of β-(1,4)/ β-(1,6)-galactobioses indicated that the preferred substrate was preferentially depleted from the culture supernatant. This established that the poor growth on the non-preferred β-(1,4) was due to inefficient uptake. We solved the structure of Bal6GBP in complex with β-(1,6)-galactobiose at 1.39 Å resolution, revealing the structural basis of this strict selectivity. Moreover, we observed a close evolutionary relationship with the human milk disaccharide lacto-N-biose-binding protein from Bifidobacterium longum, indicating that the recognition of the non-reducing galactosyl is essentially conserved, whereas the adjacent position is diversified to fit different glycosidic linkages and monosaccharide residues. These findings indicate that oligosaccharide uptake has a pivotal role in governing selectivity for distinct growth substrates and have uncovered evolutionary trajectories that shape the diversification of sugar-uptake proteins within Bifidobacterium.

KW - ABC transport

KW - Actinobacteria

KW - Bifidobacteria

KW - Crystal structure

KW - Enzyme kinetics

KW - Galactoogliosaccharides (GOS)

KW - Human milk ogliosaccharides (HMO)

KW - Human gut microbiota

KW - Isothermal titration calorimetry (ITC)

KW - Microbiome

KW - Prebitoic

KW - Probiotic

KW - Protein evolution

KW - Surface plasmon resonance (SPR)

U2 - 10.1074/jbc.RA119.008843

DO - 10.1074/jbc.RA119.008843

M3 - Journal article

VL - 294

SP - 11701

EP - 11711

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 31

ER -