This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tsujibo, H. Articles by Inamori, Y. Search for Related Content PubMed PubMed Citation Articles by Tsujibo, H. Articles by Inamori, Y.

 Previous Article  |  Next Article 

Journal of Bacteriology, February 2004, p. 1029-1037, Vol. 186, No. 4
0021-9193/04/$08.00+0     DOI: 10.1128/JB.186.4.1029-1037.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Molecular Characterization of a High-Affinity Xylobiose Transporter of Streptomyces thermoviolaceus OPC-520 and Its Transcriptional Regulation

Hiroshi Tsujibo,^* Mitsuo Kosaka, Sadao Ikenishi, Takaji Sato, Katsushiro Miyamoto, and Yoshihiko Inamori

Department of Microbiology, Osaka University of Pharmaceutical Sciences, Takatsuki, Osaka 569-1094, Japan

Received 9 July 2003/ Accepted 3 November 2003

Streptomyces thermoviolaceus OPC-520 secretes two types of xylanases (StxI and StxII), an acetyl xylan esterase (StxIII), and an -L-arabinofuranosidase (StxIV) in the presence of xylan. Xylan degradation products (mainly xylobiose) produced by the action of these enzymes entered the cell and were then degraded to xylose by an intracellular ß-xylosidase (BxlA). A gene cluster involved in xylanolytic system of the strain was cloned and sequenced upstream of and including a BxlA-encoding gene (bxlA). The gene cluster consisted of four different open reading frames organized in the order bxlE, bxlF, bxlG, and bxlA. Reverse transcriptase PCR analysis revealed that the gene cluster is transcribed as polycistronic mRNA. The deduced gene products, comprising BxlE (a sugar-binding lipoprotein), BxlF (an integral membrane protein), and BxlG (an integral membrane protein), showed similarity to components of the bacterial ATP-binding cassette (ABC) transport system; however, the gene for the ATP binding protein was not linked to the bxl operon. The soluble recombinant BxlE protein was analyzed for its binding activity for xylooligosaccharides. The protein showed high-level affinity for xylobiose (K_d = 8.75 x 10^-9 M) and for xylotriose (K_d = 8.42 x 10^-8 M). Antibodies raised against the recombinant BxlE recognized the detergent-soluble BxlE isolated from S. thermoviolaceus membranes. The deduced BxlF and BxlG proteins are predicted to be integral membrane proteins. These proteins contained the conserved EAA loop (between the fourth and the fifth membrane-spanning segments) which is characteristic of membrane proteins from binding-protein-dependent ABC transporters. In addition, the bxlR gene located upstream of the bxl operon was cloned and expressed in Escherichia coli. The bxlR gene encoded a 343-residue polypeptide that is highly homologous to members of the GalR/LacI family of bacterial transcriptional regulators. The purified BxlR protein specifically bound to a 4-bp inverted sequence overlapping the -10 region of the bxl operon. The binding of BxlR to the site was inhibited specifically by low concentrations of xylobiose. This site was also present in the region located between stxI and stxIV and in the upstream region of stxII. BxlR specifically bound to the regions containing the inverted sequence. These results suggest that BxlR might act as a repressor of the genes involved not only in the uptake system of xylan degradation products but also in xylan degradation of S. thermoviolaceus OPC-520.

---

* Corresponding author. Mailing address: Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Osaka 569-1094, Japan. Phone and fax: (81-726) 90-1057. E-mail: tsujibo{at}gly.oups.ac.jp.

---

Journal of Bacteriology, February 2004, p. 1029-1037, Vol. 186, No. 4
0021-9193/04/$08.00+0     DOI: 10.1128/JB.186.4.1029-1037.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Saito, A., Fujii, T., Shinya, T., Shibuya, N., Ando, A., Miyashita, K. (2008). The msiK gene, encoding the ATP-hydrolysing component of N,N'-diacetylchitobiose ABC transporters, is essential for induction of chitinase production in Streptomyces coelicolor A3(2). Microbiology 154: 3358-3365 [Abstract] [Full Text]  
• Saito, A., Shinya, T., Miyamoto, K., Yokoyama, T., Kaku, H., Minami, E., Shibuya, N., Tsujibo, H., Nagata, Y., Ando, A., Fujii, T., Miyashita, K. (2007). The dasABC Gene Cluster, Adjacent to dasR, Encodes a Novel ABC Transporter for the Uptake of N,N'-Diacetylchitobiose in Streptomyces coelicolor A3(2). Appl. Environ. Microbiol. 73: 3000-3008 [Abstract] [Full Text]  
• Lykidis, A., Mavromatis, K., Ivanova, N., Anderson, I., Land, M., DiBartolo, G., Martinez, M., Lapidus, A., Lucas, S., Copeland, A., Richardson, P., Wilson, D. B., Kyrpides, N. (2007). Genome Sequence and Analysis of the Soil Cellulolytic Actinomycete Thermobifida fusca YX. J. Bacteriol. 189: 2477-2486 [Abstract] [Full Text]  
• Shulami, S., Zaide, G., Zolotnitsky, G., Langut, Y., Feld, G., Sonenshein, A. L., Shoham, Y. (2007). A Two-Component System Regulates the Expression of an ABC Transporter for Xylo-Oligosaccharides in Geobacillus stearothermophilus. Appl. Environ. Microbiol. 73: 874-884 [Abstract] [Full Text]  
• Nanavati, D. M., Thirangoon, K., Noll, K. M. (2006). Several Archaeal Homologs of Putative Oligopeptide-Binding Proteins Encoded by Thermotoga maritima Bind Sugars. Appl. Environ. Microbiol. 72: 1336-1345 [Abstract] [Full Text]  
• Conners, S. B., Montero, C. I., Comfort, D. A., Shockley, K. R., Johnson, M. R., Chhabra, S. R., Kelly, R. M. (2005). An Expression-Driven Approach to the Prediction of Carbohydrate Transport and Utilization Regulons in the Hyperthermophilic Bacterium Thermotoga maritima. J. Bacteriol. 187: 7267-7282 [Abstract] [Full Text]