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. 2018 Aug 3;9:1803.
doi: 10.3389/fmicb.2018.01803. eCollection 2018.

Further Elucidation of Galactose Utilization in Lactococcus lactis MG1363

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Free PMC article

Further Elucidation of Galactose Utilization in Lactococcus lactis MG1363

Ana Solopova et al. Front Microbiol. .
Free PMC article

Abstract

Since the 1970s, galactose metabolism in Lactococcus lactis has been in debate. Different studies led to diverse outcomes making it difficult to conclude whether galactose uptake was PEP- or ATP- dependent and decide what the exact connection was between galactose and lactose uptake and metabolism. It was shown that some Lactococcus strains possess two galactose-specific systems - a permease and a PTS, even if they lack the lactose utilization plasmid, proving that a lactose-independent PTSGal exists. However, the PTSGal transporter was never identified. Here, with the help of transcriptome analyses and genetic knock-out mutants, we reveal the identities of two low-affinity galactose PTSs. A novel plant-niche-related PTS component Llmg_0963 forming a hybrid transporter Llmg_0963PtcBA and a glucose/mannose-specific PTS are shown to be involved in galactose transport in L. lactis MG1363.

Keywords: GalP; Lactococcus lactis; PEP-transferase system; PTS; galactose transporter.

Figures

FIGURE 1
FIGURE 1
Growth of Lactococcus lactis strains in CDM supplemented with 5 mM of galactose (red) or glucose (black). (A) L. lactis MGGal+. (B) L. lactis MG1363.
FIGURE 2
FIGURE 2
Growth of L. lactis strains in CDM: (A) supplemented with 50 mM galactose (B) supplemented with 5 mM galactose. Average growth of strains is shown.
FIGURE 3
FIGURE 3
Genomic organization of PTS clusters on L. lactis MG1363 chromosome. (A) Genes coding for cellobiose/glucose-specific PTS PtcABC components (B) putative plant sugar utilization cluster, specifying a predicted PTS-EIIC component, Llmg_0963. Right/left bent arrows, promoter; cre – catabolite-responsive element, a CcpA operator sequence.
FIGURE 4
FIGURE 4
Galactose metabolism in L. lactis MG1363. galP encodes galactose permease; llmg_0963ptcBA and ptnCDBA code for low-affinity galactose PTSs. galM, galactose mutarotase; galK, galactokinase; galT, galactose 1-phosphate uridylyltransferase; galE, UDP-galactose 4-epimerase are the Leloir pathway enzymes-encoding genes; pgm,α-phosphoglucomutase.

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References

    1. Abranches J., Chen Y. Y., Burne R. A. (2004). Galactose metabolism by Streptococcus mutans. Appl. Environ. Microbiol. 70 6047–6052. 10.1128/AEM.70.10.6047-6052.2004 - DOI - PMC - PubMed
    1. Aleksandrzak-Piekarczyk T., Polak J., Jezierska B., Renault P., Bardowski J. (2011). Genetic characterization of the CcpA-dependent, cellobiose-specific PTS system comprising CelB, PtcB and PtcA that transports lactose in Lactococcus lactis IL1403. Int. J. Food Microbiol. 145 186–194. 10.1016/j.ijfoodmicro.2010.12.011 - DOI - PubMed
    1. Bachmann H., Fischlechner M., Rabbers I., Barfa N., Branco dos Santos F., Molenaar D., et al. (2013). Availability of public goods shapes the evolution of competing metabolic strategies. Proc. Natl. Acad. Sci. U.S.A. 110 14302–14307. 10.1073/pnas.1308523110 - DOI - PMC - PubMed
    1. Bachmann H., Starrenburg M. J. C., Molenaar D., Kleerebezem M., van Hylckama Vlieg J. E. (2012). Microbial domestication signatures of Lactococcus lactis can be reproduced by experimental evolution. Genome Res. 22 115–124. 10.1101/gr.121285.111 - DOI - PMC - PubMed
    1. Barriere C., Veiga-da-Cunha M., Pons N., Guedon E., van Hijum S. A., Kok J., et al. (2005). Fructose utilization in Lactococcus lactis as a model for low-GC gram-positive bacteria: its regulator, signal, and DNA-binding site. J. Bacteriol. 187 3752–3761. 10.1128/JB.187.11.3752-3761.2005 - DOI - PMC - PubMed
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