PUL ID

PUL0582

PubMed

22660716, Appl Environ Microbiol. 2012 Aug;78(16):5612-21. doi: 10.1128/AEM.00455-12. Epub 2012 Jun 1.

Characterization method

NMR, microarray, enzyme activity assay, gene deletion mutant and growth assay

Genomic accession number

AM406671.1

Nucelotide position range

174930-179693

Substrate

lactose

Loci

llmg_0186-llmg_0190

Species

Lactococcus lactis/1358

Degradation or Biosynthesis

degradation

Gene Name

Locus Tag

Protein ID

Gene Position

GenBank Contig Range

EC Number

- llmg_0186 CAL96792.1 0 - 1092 (+) AM406671.1:174930-176022 -
celB llmg_0187 CAL96793.1 1191 - 2676 (+) AM406671.1:176121-177606 2.7.1.69
- llmg_0188 CAL96794.1 2801 - 3008 (+) AM406671.1:177731-177938 -
- llmg_0189 CAL96795.1 3004 - 3199 (+) AM406671.1:177934-178129 -
bglS llmg_0190 CAL96796.1 3327 - 4764 (+) AM406671.1:178257-179694 3.2.1.21

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 1092 (+) CDS No
celB 1192 - 2676 (+) TC: gnl|TC-DB|Q9CJ32|4.A.3.2.4 Yes
- 2802 - 3008 (+) other Yes
- 3005 - 3199 (+) other Yes
bglS 3328 - 4764 (+) CAZyme: GH1 Yes

PUL ID

PUL0582

PubMed

22660716, Appl Environ Microbiol. 2012 Aug;78(16):5612-21. doi: 10.1128/AEM.00455-12. Epub 2012 Jun 1.

Title

A specific mutation in the promoter region of the silent cel cluster accounts for the appearance of lactose-utilizing Lactococcus lactis MG1363.

Author

Solopova A, Bachmann H, Teusink B, Kok J, Neves AR, Kuipers OP

Abstract

The Lactococcus lactis laboratory strain MG1363 has been described to be unable to utilize lactose. However, in a rich medium supplemented with lactose as the sole carbon source, it starts to grow after prolonged incubation periods. Transcriptome analyses showed that L. lactis MG1363 Lac(+) cells expressed celB, encoding a putative cellobiose-specific phosphotransferase system (PTS) IIC component, which is normally silent in MG1363 Lac(-) cells. Nucleotide sequence analysis of the cel cluster of a Lac(+) isolate revealed a change from one of the guanines to adenine in the promoter region. We showed here that one particular mutation, taking place at increased frequency, accounts for the lactose-utilizing phenotype occurring in MG1363 cultures. The G-to-A transition creates a -10 element at an optimal distance from the -35 element. Thus, a fully active promoter is created, allowing transcription of the otherwise cryptic cluster. Nuclear magnetic resonance (NMR) spectroscopy results show that MG1363 Lac(+) uses a novel pathway of lactose utilization.