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 Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ekborg, N. A. Articles by Hutcheson, S. W. Search for Related Content PubMed PubMed Citation Articles by Ekborg, N. A. Articles by Hutcheson, S. W. Agricola Articles by Ekborg, N. A. Articles by Hutcheson, S. W.

Genomic and Proteomic Analyses of the Agarolytic System Expressed by Saccharophagus degradans 2-40

Department of Cell Biology and Molecular Genetics, Microbiology Building, University of Maryland, College Park, Maryland 20742,¹ Department of Marine and Estuarine Environmental Studies, Microbiology Building, University of Maryland, College Park, Maryland 20742,² Architecture et Fonction des Macromolecules Biologiques, UMR6908, CNRS, and Universites Aix-Marseille I and II, Case 932, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France³

Received 29 November 2005/ Accepted 6 March 2006

Saccharophagus degradans 2-40 (formerly Microbulbifer degradans 2-40) is a marine gamma-subgroup proteobacterium capable of degrading many complex polysaccharides, such as agar. While several agarolytic systems have been characterized biochemically, the genetics of agarolytic systems have been only partially determined. By use of genomic, proteomic, and genetic approaches, the components of the S. degradans 2-40 agarolytic system were identified. Five agarases were identified in the S. degradans 2-40 genome. Aga50A and Aga50D include GH50 domains. Aga86C and Aga86E contain GH86 domains, whereas Aga16B carries a GH16 domain. Novel family 6 carbohydrate binding modules (CBM6) were identified in Aga16B and Aga86E. Aga86C has an amino-terminal acylation site, suggesting that it is surface associated. Aga16B, Aga86C, and Aga86E were detected by mass spectrometry in agarolytic fractions obtained from culture filtrates of agar-grown cells. Deletion analysis revealed that aga50A and aga86E were essential for the metabolism of agarose. Aga16B was shown to endolytically degrade agarose to release neoagarotetraose, similarly to a ß-agarase I, whereas Aga86E was demonstrated to exolytically degrade agarose to form neoagarobiose. The agarolytic system of S. degradans 2-40 is thus predicted to be composed of a secreted endo-acting GH16-dependent depolymerase, a surface-associated GH50-dependent depolymerase, an exo-acting GH86-dependent agarase, and an -neoagarobiose hydrolase to release galactose from agarose.

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

This article has been cited by other articles:

• Henshaw, J., Horne-Bitschy, A., van Bueren, A. L., Money, V. A., Bolam, D. N., Czjzek, M., Ekborg, N. A., Weiner, R. M., Hutcheson, S. W., Davies, G. J., Boraston, A. B., Gilbert, H. J. (2006). Family 6 Carbohydrate Binding Modules in beta-Agarases Display Exquisite Selectivity for the Non-reducing Termini of Agarose Chains. J. Biol. Chem. 281: 17099-17107 [Abstract] [Full Text]