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Genetic Characterization of the CcpA-Dependent, Cellobiose-Specific PTS System Comprising CelB, PtcB and PtcA that Transports Lactose in Lactococcus lactis IL1403.

Aleksandrzak-Piekarczyk, Tamara and Polak, Jolanta and Jezierska, Beata and Renault, Pierre and Bardowski, Jacek K. (2011) Genetic Characterization of the CcpA-Dependent, Cellobiose-Specific PTS System Comprising CelB, PtcB and PtcA that Transports Lactose in Lactococcus lactis IL1403. International Journal of Food Microbiology . ISSN 0168-1605

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Official URL: http://www.elsevier.com/wps/find/journaldescriptio...

Abstract

Lactose metabolism is one of the most important areas of research on Lactic Acid Bacteria (LAB). In rapidly acidifying industrial Lactococcus lactis strains, lactose is transported by a lactose-specific phosphotransferase system (PTS) encoded by a plasmid. However, an alternative lactose catabolic pathway was evidenced in the plasmid-cured, and thus initially lactose-negative L. lactis IL1403. We showed that in this strain the chromosomally-encoded cellobiose-specific PTS system comprising the celB, ptcB and ptcA genes is also able to transport lactose. By expression studies in the wild type IL1403 strain and IBB550, its ccpA-deficient derivative, we demonstrated that celB, ptcB and ptcA are tightly regulated by the general catabolite repression system, whereas celB additionally requires the presence of cellobiose to be fully induced. The comparison of expression levels of sugar catabolic genes indicated that the efficiency of CcpA-mediated catabolic repression depends on conservation of the cre sequence, and that in the case of perfect matching with the cre consensus, CcpA still drives a strong repression even under non-repressing conditions.

Item Type:Article
Uncontrolled Keywords:lactose, cellobiose assimilation; phosphotransferase system (PTS); catabolite repression; Lactococcus lactis
Subjects:Q Science > Q Science (General)
Divisions:Department of Microbial Biochemistry
ID Code:211
Deposited By: dr Tamara Aleksandrzak-Piekarczyk
Deposited On:21 Feb 2012 09:21
Last Modified:14 Oct 2014 11:33

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