This Article Full Text Full Text (PDF) Supplemental material 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 Google Scholar Google Scholar Articles by Angelov, A. Articles by Liebl, W. Search for Related Content PubMed PubMed Citation Articles by Angelov, A. Articles by Liebl, W.

 Previous Article  |  Next Article 

Journal of Bacteriology, October 2006, p. 7123-7131, Vol. 188, No. 20
0021-9193/06/$08.00+0     doi:10.1128/JB.00757-06
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

Molecular and Biochemical Characterization of -Glucosidase and -Mannosidase and Their Clustered Genes from the Thermoacidophilic Archaeon Picrophilus torridus

Institute of Microbiology and Genetics, University of Goettingen, Grisebachstrasse 8, D-37077 Goettingen, Germany,¹ Institute of Microbiology, Department of Bacterial Genetics, Warsaw University, Miecznikowa 1, 02-096 Warsaw, Poland²

Received 26 May 2006/ Accepted 30 July 2006

The genes encoding a putative -glucosidase (aglA) and an -mannosidase (manA) appear to be physically clustered in the genome of the extreme acidophile Picrophilus torridus, a situation not found previously in any other organism possessing aglA or manA homologs. While archaeal -glucosidases have been described, no -mannosidase enzymes from the archaeal kingdom have been reported previously. Transcription start site mapping and Northern blot analysis revealed that despite their colinear orientation and the small intergenic space, the genes are independently transcribed, both producing leaderless mRNA. aglA and manA were cloned and overexpressed in Escherichia coli, and the purified recombinant enzymes were characterized with respect to their physicochemical and biochemical properties. AglA displayed strict substrate specificity and hydrolyzed maltose, as well as longer -1,4-linked maltooligosaccharides. ManA, on the other hand, hydrolyzed all possible linkage types of -glycosidically linked mannose disaccharides and was able to hydrolyze 3,6-mannopentaose, which represents the core structure of many triantennary N-linked carbohydrates in glycoproteins. The probable physiological role of the two enzymes in the utilization of exogenous glycoproteins and/or in the turnover of the organism's own glycoproteins is discussed.

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