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Journal of Bacteriology, April 2008, p. 2298-2305, Vol. 190, No. 7
0021-9193/08/$08.00+0     doi:10.1128/JB.01794-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Molecular and Physiological Role of the Trehalose-Hydrolyzing {alpha}-Glucosidase from Thermus thermophilus HB27{triangledown} ,{dagger}

Susana Alarico,1 Milton S. da Costa,2 and Nuno Empadinhas1*

Centro de Neurociências e Biologia Celular, Departamento de Zoologia, Universidade de Coimbra, 3004-517 Coimbra, Portugal,1 Departamento de Bioquímica, Universidade de Coimbra, 3001-401 Coimbra, Portugal2

Received 13 November 2007/ Accepted 11 January 2008

Trehalose supports the growth of Thermus thermophilus strain HB27, but the absence of obvious genes for the hydrolysis of this disaccharide in the genome led us to search for enzymes for such a purpose. We expressed a putative {alpha}-glucosidase gene (TTC0107), characterized the recombinant enzyme, and found that the preferred substrate was {alpha},{alpha}-1,1-trehalose, a new feature among {alpha}-glucosidases. The enzyme could also hydrolyze the disaccharides kojibiose and sucrose ({alpha}-1,2 linkage), nigerose and turanose ({alpha}-1,3), leucrose ({alpha}-1,5), isomaltose and palatinose ({alpha}-1,6), and maltose ({alpha}-1,4) to a lesser extent. Trehalose was not, however, a substrate for the highly homologous {alpha}-glucosidase from T. thermophilus strain GK24. The reciprocal replacement of a peptide containing eight amino acids in the {alpha}-glucosidases from strains HB27 (LGEHNLPP) and GK24 (EPTAYHTL) reduced the ability of the former to hydrolyze trehalose and provided trehalose-hydrolytic activity to the latter, showing that LGEHNLPP is necessary for trehalose recognition. Furthermore, disruption of the {alpha}-glucosidase gene significantly affected the growth of T. thermophilus HB27 in minimal medium supplemented with trehalose, isomaltose, sucrose, or palatinose, to a lesser extent with maltose, but not with cellobiose (not a substrate for the {alpha}-glucosidase), indicating that the {alpha}-glucosidase is important for the assimilation of those four disaccharides but that it is also implicated in maltose catabolism.

* Corresponding author. Mailing address: Centro de Neurociências e Biologia Celular, Departamento de Zoologia, Universidade de Coimbra, 3004-517 Coimbra, Portugal. Phone: 351-239824024. Fax: 351-239855789. E-mail: numenius{at}cnc.uc.pt

{triangledown} Published ahead of print on 25 January 2008.

{dagger} Supplemental material for this article may be found at http://jb.asm.org/.

Journal of Bacteriology, April 2008, p. 2298-2305, Vol. 190, No. 7
0021-9193/08/$08.00+0     doi:10.1128/JB.01794-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Pokusaeva, K., O'Connell-Motherway, M., Zomer, A., Fitzgerald, G. F., van Sinderen, D. (2009). Characterization of Two Novel {alpha}-Glucosidases from Bifidobacterium breve UCC2003. Appl. Environ. Microbiol. 75: 1135-1143 [Abstract] [Full Text]  


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