Lactobacillus surface layer proteins: structure, function and applications

Hynönen, Ulla; Palva, Airi

doi:10.1007/s00253-013-4962-2

Cited by 215 publications

(212 citation statements)

References 194 publications

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“…Recently, the first extracellular glycoside hydrolase from L. acidophilus NCFM was shown to be a ␤-N-acetylglucosaminidase autolysin essential for cell division (40). This enzyme harbors a surface layer association protein (SLAP) domain (Pfam family PF03217 [41]) that confers noncovalent attachment to the proteinaceous outermost surface layer common in several lactobacilli (42). SLAP domains also occur at the C termini of other functionally important proteins such as autolysins, fibronectin and mucin binding proteins, putative peptidases, nucleases, and glycoside hydrolases as well as polysaccharide lyases according to the Pfam database (41).…”

Section: Discussionmentioning

confidence: 99%

An Extracellular Cell-Attached Pullulanase Confers Branched α-Glucan Utilization in Human Gut Lactobacillus acidophilus

Møller

Goh

Rasmussen

et al. 2017

Appl Environ Microbiol

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Of the few predicted extracellular glycan-active enzymes, glycoside hydrolase family 13 subfamily 14 (GH13_14) pullulanases are the most common in human gut lactobacilli. These enzymes share a unique modular organization, not observed in other bacteria, featuring a catalytic module, two starch binding modules, a domain of unknown function, and a C-terminal surface layer association protein (SLAP) domain. Here, we explore the specificity of a representative of this group of pullulanases, Lactobacillus acidophilus Pul13_14 (LaPul13_14), and its role in branched ␣-glucan metabolism in the well-characterized Lactobacillus acidophilus NCFM, which is widely used as a probiotic. Growth experiments with L. acidophilus NCFM on starch-derived branched substrates revealed a preference for ␣-glucans with short branches of about two to three glucosyl moieties over amylopectin with longer branches. Cell-attached debranching activity was measurable in the presence of ␣-glucans but was repressed by glucose. The debranching activity is conferred exclusively by LaPul13_14 and is abolished in a mutant strain lacking a functional LaPul13_14 gene. Hydrolysis kinetics of recombinant LaPul13_14 confirmed the preference for short-branched ␣-glucan oligomers consistent with the growth data. Curiously, this enzyme displayed the highest catalytic efficiency and the lowest K m reported for a pullulanase. Inhibition kinetics revealed mixed inhibition by ␤-cyclodextrin, suggesting the presence of additional glucan binding sites besides the active site of the enzyme, which may contribute to the unprecedented substrate affinity. The enzyme also displays high thermostability and higher activity in the acidic pH range, reflecting adaptation to the physiologically challenging conditions in the human gut.IMPORTANCE Starch is one of the most abundant glycans in the human diet. Branched ␣-1,6-glucans in dietary starch and glycogen are nondegradable by human enzymes and constitute a metabolic resource for the gut microbiota. The role of healthbeneficial lactobacilli prevalent in the human small intestine in starch metabolism remains unexplored in contrast to colonic bacterial residents. This study highlights the pivotal role of debranching enzymes in the breakdown of starchy branched ␣-glucan oligomers (␣-limit dextrins) by human gut lactobacilli exemplified by Lactobacillus acidophilus NCFM, which is one of the best-characterized strains used as probiotics. Our data bring novel insight into the metabolic preference of L. acidophilus for ␣-glucans with short ␣-1,6-branches. The unprecedented affinity of the debranching enzyme that confers growth on these substrates reflects its adaptation to the nutrient-competitive gut ecological niche and constitutes a potential advantage in cross-feeding from human and bacterial dietary starch metabolism.

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Section: Discussionmentioning

confidence: 99%

An Extracellular Cell-Attached Pullulanase Confers Branched α-Glucan Utilization in Human Gut Lactobacillus acidophilus

Møller

Goh

Rasmussen

et al. 2017

Appl Environ Microbiol

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“…The inhibition observed in the previous study may have resulted from an unspecific effect caused by the higher hydrophobicity of the BopA (lipo)proteins used in the study. Accordingly, the surface layer (S-layer) proteins of Lactobacillus, which are rich in hydrophobic amino acids (33), have been shown to inhibit the adhesion of S. aureus to Caco-2 cells (34). Furthermore, it has been shown that cell surface hydrophobicity indicates good adhesion potential for bacteria and that the high hydrophobicity of the cell surface of a probiotic strain correlates well with its capacity to inhibit pathogen adhesion through steric hindrance (35).…”

Section: Discussionmentioning

confidence: 99%

BopA Does Not Have a Major Role in the Adhesion of Bifidobacterium bifidum to Intestinal Epithelial Cells, Extracellular Matrix Proteins, and Mucus

Kainulainen

Reunanen

Hiippala

et al. 2013

Appl Environ Microbiol

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The ability of bifidobacteria to adhere to the intestine of the human host is considered to be important for efficient colonization and achieving probiotic effects. Bifidobacterium bifidum strains DSM20456 and MIMBb75 adhere well to the human intestinal cell lines Caco-2 and HT-29. The surface lipoprotein BopA was previously described to be involved in mediating adherence of B. bifidum to epithelial cells, but thioacylated, purified BopA inhibited the adhesion of B. bifidum to epithelial cells in competitive adhesion assays only at very high concentrations, indicating an unspecific effect. In this study, the role of BopA in the adhesion of B. bifidum was readdressed. The gene encoding BopA was cloned and expressed without its lipobox and hydrophobic signal peptide in Escherichia coli, and an antiserum against the recombinant BopA was produced. The antiserum was used to demonstrate the abundant localization of BopA on the cell surface of B. bifidum. However, blocking of B. bifidum BopA with specific antiserum did not reduce adhesion of bacteria to epithelial cell lines, arguing that BopA is not an adhesin. Also, adhesion of B. bifidum to human colonic mucin and fibronectin was found to be BopA independent. The recombinant BopA bound only moderately to human epithelial cells and colonic mucus, and it failed to bind to fibronectin. Thus, our results contrast the earlier findings on the major role of BopA in adhesion, indicating that the strong adhesion of B. bifidum to epithelial cell lines is BopA independent.

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“…Some experimental data give hints that the proteases cleave peptide bonds in the peptidoglycan or the outer membrane of Gram-negative bacteria [41]. Another possible target are S-layer proteins, which comprise the outer cell border of many Archaea and Gram-positive bacteria, including lactic acid bacteria [22] [42] [43]. In this study, we found that the purified protease degrades S-layer proteins from L. brevis B 190, and previously, we demonstrated that the S-layer of Lactobacillus hilgardii B706 was degraded by the culture supernatant of S. albidoflavus B 578 [22].…”

Section: Discussionmentioning

confidence: 99%

Studies on Two Exoenzymes Which Lyse Wine-Spoiling Bacteria

Sébastian¹,

Claus²,

König³

2014

AiM

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Microorganisms play an important role in the conversion of grape juice into wine. Different species of yeast are mainly responsible for the production of ethanol. Lactic acid bacteria also occur regularly in must or wine. They are mostly undesirable due to their capacity to produce winespoiling compounds. Especially strains of Lactobacillus brevis are able to produce biogenic amines as well as precursors of ethyl carbamate and different off-flavours (N-heterocycles, volatile phenols). By excessive formation of acetic acid some lactobacilli may even induce slow/stuck grape juice fermentations. In conventional winemaking, additions of sulphite or lysozyme are used to inhibit the growth of spoilage microorganisms. There is a strong interest in finding alternatives, because of the reduced activity of lysozyme in the wine milieu, a limited growth-inhibiting activity against lactic acid bacteria, and some health risks described regarding the application of sulphite. We found that a culture supernatant of Streptomyces albidoflavus B 578 lysed all bacteria previously isolated from must and wine samples (Acetobacter sp., Lactobacillus sp., Leuconostoc sp., Oenococcus oeni, Pediococcus sp., Staphylococcus sp.) including 35 strains of L. brevis. Two bacteriolytic exoenzymes were isolated and characterized from the streptomycete: a muramidase (24 kDa) and a protease (17 kDa). Both hydrolyzed cell wall components of L. brevis (peptidoglycan, S-layer proteins) and were active under wine-relevant conditions.

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Lactobacillus surface layer proteins: structure, function and applications

Cited by 215 publications

References 194 publications

An Extracellular Cell-Attached Pullulanase Confers Branched α-Glucan Utilization in Human Gut Lactobacillus acidophilus

An Extracellular Cell-Attached Pullulanase Confers Branched α-Glucan Utilization in Human Gut Lactobacillus acidophilus

BopA Does Not Have a Major Role in the Adhesion of Bifidobacterium bifidum to Intestinal Epithelial Cells, Extracellular Matrix Proteins, and Mucus

Studies on Two Exoenzymes Which Lyse Wine-Spoiling Bacteria

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