Cell-surface protein YwfG of Lactococcus lactis binds to α-1,2-linked mannose

Lactococcus lactis strains are used as starter cultures in the production of fermented dairy and vegetable foods, but the species also occurs in other niches such as plant material. Lactococcus lactis subsp. lactis G50 (G50) is a plant-derived strain and potential candidate probiotics. Western blott...

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Main Authors: Wataru Tsuchiya, Zui Fujimoto, Noritoshi Inagaki, Hiroyuki Nakagawa, Miwa Tanaka, Hiromi Kimoto-Nira, Toshimasa Yamazaki, Chise Suzuki
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2023-01-01
Series:PLoS ONE
Online Access:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9815576/?tool=EBI
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author Wataru Tsuchiya
Zui Fujimoto
Noritoshi Inagaki
Hiroyuki Nakagawa
Miwa Tanaka
Hiromi Kimoto-Nira
Toshimasa Yamazaki
Chise Suzuki
author_facet Wataru Tsuchiya
Zui Fujimoto
Noritoshi Inagaki
Hiroyuki Nakagawa
Miwa Tanaka
Hiromi Kimoto-Nira
Toshimasa Yamazaki
Chise Suzuki
author_sort Wataru Tsuchiya
collection DOAJ
description Lactococcus lactis strains are used as starter cultures in the production of fermented dairy and vegetable foods, but the species also occurs in other niches such as plant material. Lactococcus lactis subsp. lactis G50 (G50) is a plant-derived strain and potential candidate probiotics. Western blotting of cell-wall proteins using antibodies generated against whole G50 cells detected a 120-kDa protein. MALDI-TOF MS analysis identified it as YwfG, a Leu-Pro-any-Thr-Gly cell-wall-anchor-domain–containing protein. Based on a predicted domain structure, a recombinant YwfG variant covering the N-terminal half (aa 28–511) of YwfG (YwfG28−511) was crystallized and the crystal structure was determined. The structure consisted of an L-type lectin domain, a mucin-binding protein domain, and a mucus-binding protein repeat. Recombinant YwfG variants containing combinations of these domains (YwfG28–270, YwfG28–336, YwfG28−511, MubR4) were prepared and their interactions with monosaccharides were examined by isothermal titration calorimetry; the only interaction observed was between YwfG28–270, which contained the L-type lectin domain, and d-mannose. Among four mannobioses, α-1,2-mannobiose had the highest affinity for YwfG28–270 (dissociation constant = 34 μM). YwfG28–270 also interacted with yeast mannoproteins and yeast mannan. Soaking of the crystals of YwfG28–511 with mannose or α-1,2-mannobiose revealed that both sugars bound to the L-type lectin domain in a similar manner, although the presence of the mucin-binding protein domain and the mucus-binding protein repeat within the recombinant protein inhibited the interaction between the L-type lectin domain and mannose residues. Three of the YwfG variants (except MubR4) induced aggregation of yeast cells. Strain G50 also induced aggregation of yeast cells, which was abolished by deletion of ywfG from G50, suggesting that surface YwfG contributes to the interaction with yeast cells. These findings provide new structural and functional insights into the interaction between L. lactis and its ecological niche via binding of the cell-surface protein YwfG with mannose.
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spelling doaj.art-8043410ad6204e23b3886dca9a9bbe6c2023-01-08T05:32:17ZengPublic Library of Science (PLoS)PLoS ONE1932-62032023-01-01181Cell-surface protein YwfG of Lactococcus lactis binds to α-1,2-linked mannoseWataru TsuchiyaZui FujimotoNoritoshi InagakiHiroyuki NakagawaMiwa TanakaHiromi Kimoto-NiraToshimasa YamazakiChise SuzukiLactococcus lactis strains are used as starter cultures in the production of fermented dairy and vegetable foods, but the species also occurs in other niches such as plant material. Lactococcus lactis subsp. lactis G50 (G50) is a plant-derived strain and potential candidate probiotics. Western blotting of cell-wall proteins using antibodies generated against whole G50 cells detected a 120-kDa protein. MALDI-TOF MS analysis identified it as YwfG, a Leu-Pro-any-Thr-Gly cell-wall-anchor-domain–containing protein. Based on a predicted domain structure, a recombinant YwfG variant covering the N-terminal half (aa 28–511) of YwfG (YwfG28−511) was crystallized and the crystal structure was determined. The structure consisted of an L-type lectin domain, a mucin-binding protein domain, and a mucus-binding protein repeat. Recombinant YwfG variants containing combinations of these domains (YwfG28–270, YwfG28–336, YwfG28−511, MubR4) were prepared and their interactions with monosaccharides were examined by isothermal titration calorimetry; the only interaction observed was between YwfG28–270, which contained the L-type lectin domain, and d-mannose. Among four mannobioses, α-1,2-mannobiose had the highest affinity for YwfG28–270 (dissociation constant = 34 μM). YwfG28–270 also interacted with yeast mannoproteins and yeast mannan. Soaking of the crystals of YwfG28–511 with mannose or α-1,2-mannobiose revealed that both sugars bound to the L-type lectin domain in a similar manner, although the presence of the mucin-binding protein domain and the mucus-binding protein repeat within the recombinant protein inhibited the interaction between the L-type lectin domain and mannose residues. Three of the YwfG variants (except MubR4) induced aggregation of yeast cells. Strain G50 also induced aggregation of yeast cells, which was abolished by deletion of ywfG from G50, suggesting that surface YwfG contributes to the interaction with yeast cells. These findings provide new structural and functional insights into the interaction between L. lactis and its ecological niche via binding of the cell-surface protein YwfG with mannose.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9815576/?tool=EBI
spellingShingle Wataru Tsuchiya
Zui Fujimoto
Noritoshi Inagaki
Hiroyuki Nakagawa
Miwa Tanaka
Hiromi Kimoto-Nira
Toshimasa Yamazaki
Chise Suzuki
Cell-surface protein YwfG of Lactococcus lactis binds to α-1,2-linked mannose
PLoS ONE
title Cell-surface protein YwfG of Lactococcus lactis binds to α-1,2-linked mannose
title_full Cell-surface protein YwfG of Lactococcus lactis binds to α-1,2-linked mannose
title_fullStr Cell-surface protein YwfG of Lactococcus lactis binds to α-1,2-linked mannose
title_full_unstemmed Cell-surface protein YwfG of Lactococcus lactis binds to α-1,2-linked mannose
title_short Cell-surface protein YwfG of Lactococcus lactis binds to α-1,2-linked mannose
title_sort cell surface protein ywfg of lactococcus lactis binds to α 1 2 linked mannose
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9815576/?tool=EBI
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