PUL ID

PUL0531

PubMed

12618440, J Bacteriol. 2003 Mar;185(6):1776-82. doi: 10.1128/JB.185.6.1776-1782.2003.

Characterization method

clone and expression,enzyme activity assay

Genomic accession number

NZ_HG326223.1

Nucelotide position range

172559-177453

Substrate

chitobiose

Loci

chbB-chbC-bglA-chbR-chbG

Species

Serratia marcescens/615

Degradation or Biosynthesis

degradation

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 318 (+) TC: gnl|TC-DB|Q8L3C3|4.A.3.2.5 Yes
chbC 331 - 1692 (+) TC: gnl|TC-DB|Q8L3C2|4.A.3.2.5 Yes
- 1736 - 3121 (+) CAZyme: GH1 Yes
chbR 3137 - 3985 (+) STP: STP|AraC_binding,STP|HTH_18 No
chbG 4134 - 4895 (+) CDS No

PUL ID

PUL0531

PubMed

12618440, J Bacteriol. 2003 Mar;185(6):1776-82. doi: 10.1128/JB.185.6.1776-1782.2003.

Title

Uptake of N,N'-diacetylchitobiose [(GlcNAc)2] via the phosphotransferase system is essential for chitinase production by Serratia marcescens 2170.

Author

Uchiyama T, Kaneko R, Yamaguchi J, Inoue A, Yanagida T, Nikaidou N, Regue M, Watanabe T

Abstract

The chiR gene of Serratia marcescens 2170, encoding a LysR-type transcriptional activator, was identified previously as an essential factor for expression of chitinases and a chitin-binding protein, CBP21. To identify other genes that are essential for chitinase production, transposon mutagenesis with mini-Tn5Km1 was carried out, and 25 mutants that were unable to produce chitinases and CBP21 were obtained. Analysis of the mutated gene of one of the mutants, N22, revealed the presence of a pts operon in this bacterium, and a mutation was found in ptsI in the operon. In addition to its inability to produce chitinase, N22 did not grow well on N-acetyl-D-glucosamine (GlcNAc), (GlcNAc)(2), and some other carbon sources, most of which were phosphotransferase system (PTS) sugars. Thus, the inability to produce chitinase was assumed to be caused by the defect in uptake of (GlcNAc)(2) via the PTS, considering that (GlcNAc)(2) is the minimal substrate for chitinase induction and the major product of chitin hydrolysis by chitinases of this bacterium. To confirm this assumption, the chb operon, encoding the (GlcNAc)(2)-specific enzyme II permease, was cloned by reference to its Escherichia coli counterpart, and the Serratia chb operon was shown to comprise chbB, chbC, bglA, chbR, and chbG. Disruption of chbC drastically reduced production of chitinases and CBP21 and impaired growth on colloidal chitin. These results indicate that uptake of (GlcNAc)(2) is mediated by the PTS and that the (GlcNAc)(2)-specific enzyme II permease constitutes its major pathway. Since (GlcNAc)(2) uptake is essential for induction of chitinases and CBP21 production, (GlcNAc)(2) appears to be the key molecule in recognition and utilization of chitin by S. marcescens.