PUL ID

PUL0578

PubMed

21216899, Appl Environ Microbiol. 2011 Mar;77(5):1681-90. doi: 10.1128/AEM.01786-10. Epub 2011 Jan 7.

Characterization method

qRT-PCR,enzyme activity assay,electrophoretic mobility shift assay

Genomic accession number

CP000303.1

Nucelotide position range

153080-159234

Substrate

cellodextrin

Loci

Bbr_0105-Bbr_0109

Species

Bifidobacterium breve/1685

Degradation or Biosynthesis

degradation

Gene Name

Locus Tag

Protein ID

Gene Position

GenBank Contig Range

EC Number

cldR Bbr_0105 ABE94817.1 0 - 1005 (+) CP000303.1:153080-154085 -
cldE Bbr_0106 ABE94818.1 1185 - 2493 (+) CP000303.1:154265-155573 -
cldF Bbr_0107 ABE94819.1 2571 - 3693 (+) CP000303.1:155651-156773 -
cldG Bbr_0108 ABE94820.1 3700 - 4648 (+) CP000303.1:156780-157728 -
cldC Bbr_0109 ABE94821.1 4754 - 6155 (+) CP000303.1:157834-159235 3.2.1.21

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

cldR 1 - 1005 (+) STP: STP|LacI,STP|Peripla_BP_3 No
cldE 1186 - 2493 (+) TC: gnl|TC-DB|Q9X9R7|3.A.1.1.23 Yes
cldF 2572 - 3693 (+) TC: gnl|TC-DB|Q9X9R6|3.A.1.1.23 Yes
cldG 3701 - 4648 (+) TC: gnl|TC-DB|Q9X9R5|3.A.1.1.23 Yes
cldC 4755 - 6155 (+) CAZyme: GH1 Yes

PUL ID

PUL0578

PubMed

21216899, Appl Environ Microbiol. 2011 Mar;77(5):1681-90. doi: 10.1128/AEM.01786-10. Epub 2011 Jan 7.

Title

Cellodextrin utilization by bifidobacterium breve UCC2003.

Author

Pokusaeva K, O'Connell-Motherway M, Zomer A, Macsharry J, Fitzgerald GF, van Sinderen D

Abstract

Cellodextrins, the incomplete hydrolysis products from insoluble cellulose, are accessible as a carbon source to certain members of the human gut microbiota, such as Bifidobacterium breve UCC2003. Transcription of the cldEFGC gene cluster of B. breve UCC2003 was shown to be induced upon growth on cellodextrins, implicating this cluster in the metabolism of these sugars. Phenotypic analysis of a B. breve UCC2003::cldE insertion mutant confirmed that the cld gene cluster is exclusively required for cellodextrin utilization by this commensal. Moreover, our results suggest that transcription of the cld cluster is controlled by a LacI-type regulator encoded by cldR, located immediately upstream of cldE. Gel mobility shift assays using purified CldR(His) (produced by the incorporation of a His(12)-encoding sequence into the 3' end of the cldC gene) indicate that the cldEFGC promoter is subject to negative control by CldR(His), which binds to two inverted repeats. Analysis by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) of medium samples obtained during growth of B. breve UCC2003 on a mixture of cellodextrins revealed its ability to utilize cellobiose, cellotriose, cellotetraose, and cellopentaose, with cellotriose apparently representing the preferred substrate. The cldC gene of the cld operon of B. breve UCC2003 is, to the best of our knowledge, the first described bifidobacterial beta-glucosidase exhibiting hydrolytic activity toward various cellodextrins.