PUL ID

PUL0561

PubMed

12406739, Appl Environ Microbiol. 2002 Nov;68(11):5464-71. doi: 10.1128/aem.68.11.5464-5471.2002.

Characterization method

clone and expression, enzyme activity assay

Genomic accession number

NC_004567.2

Nucelotide position range

3100330-3091774

Substrate

alpha-galactoside

Loci

lp_3483-lp_3487

Species

Lactobacillus plantarum/1590

Degradation or Biosynthesis

degradation

Gene Name

Locus Tag

Protein ID

Gene Position

GenBank Contig Range

EC Number

- LP_RS14565 WP_049788013.1 6 - 1035 (+) NC_004567.2:3100336-3101365 -
- LP_RS14560 WP_003643065.1 1362 - 3321 (+) NC_004567.2:3101692-3103651 -
- LP_RS14555 WP_011102184.1 3417 - 5634 (+) NC_004567.2:3103747-3105964 -
- LP_RS14550 WP_011102183.1 5733 - 6693 (-) NC_004567.2:3106063-3107023 -
- LP_RS14545 WP_011102182.1 6676 - 8557 (-) NC_004567.2:3107006-3108887 -

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

- 7 - 1035 (+) CDS No
- 1363 - 3321 (+) TC: gnl|TC-DB|P23936|2.A.2.2.1 Yes
- 3418 - 5634 (+) CAZyme: GH36 Yes
- 5734 - 6693 (-) other Yes
- 6677 - 8557 (-) CAZyme: GH2 Yes

PUL ID

PUL0561

PubMed

12406739, Appl Environ Microbiol. 2002 Nov;68(11):5464-71. doi: 10.1128/aem.68.11.5464-5471.2002.

Title

Characterization of the melA locus for alpha-galactosidase in Lactobacillus plantarum.

Author

Silvestroni A, Connes C, Sesma F, De Giori GS, Piard JC

Abstract

Alpha-galactosides are abundant sugars in legumes such as soy. Because of the lack of alpha-galactosidase (alpha-Gal) in the digestive tract, humans are unable to digest these sugars, which consequently induce flatulence. To develop the consumption of the otherwise highly nutritional soy products, the use of exogenous alpha-Gal is promising. In this framework, we characterized the melA gene for alpha-Gal in Lactobacillus plantarum. The melA gene encodes a cytoplasmic 84-kDa protein whose enzymatically active form occurs as oligomers. The melA gene was cloned and expressed in Escherichia coli, yielding an active alpha-Gal. We show that melA is transcribed from its own promoter, yielding a monocistronic mRNA, and that it is regulated at the transcriptional level, i.e., it is induced by melibiose but is not totally repressed by glucose. Posttranscriptional regulation by the carbon source could also occur. Upstream of melA, a putative galactoside transporter, designated RafP, was identified that shows high homology to LacS, the unique transporter for both alpha- and beta-galactosides in Streptococcus thermophilus. rafP is also expressed as a monocistronic mRNA. Downstream of melA, the lacL and lacM genes were identified that encode a heterodimeric beta-galactosidase. A putative galM gene identified in the same cluster suggests the presence of a galactose operon. These results indicate that the genes involved in galactoside catabolism are clustered in L. plantarum ATCC 8014. This first genetic characterization of melA and of its putative associated transporter, rafP, in a lactobacillus opens doors to various applications both in the manufacture of soy-derived products and in probiotic and nutraceutical issues.