Heterologous expression and biochemical characterization of an a1,2-mannosidase encoded by the Candida albicans MNS1 gene

Protein glycosylation pathways, commonly found in fungal pathogens, offer an attractive new area of study for the discovery of antifungal targets. In particular, these post-translational modifications are required for virulence and proper cell wall assembly in Candida albicans, an opportunistic huma...

Full description

Saved in:
Bibliographic Details
Published in:Memórias do Instituto Oswaldo Cruz 2008-11, Vol.103 (7), p.724-730
Main Authors: Mora-Montes, H M, Lopez-Romero, E, Zinker, S, Ponce-Noyola, P, Flores-Carreon, A
Format: Article
Language:English
Subjects:
Candida albicans
Escherichia coli
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Protein glycosylation pathways, commonly found in fungal pathogens, offer an attractive new area of study for the discovery of antifungal targets. In particular, these post-translational modifications are required for virulence and proper cell wall assembly in Candida albicans, an opportunistic human pathogen. The C. albicans MNS1 gene is predicted to encode a member of the glycosyl hydrolase family 47, with a1,2-mannosidase activity. In order to characterise its activity, we first cloned the C. albicans MNS1 gene into Escherichia coli, then expressed and purified the enzyme. The recombinant MNS1 was capable of converting a Man sub(9)GlcNAc sub(2) N-glycan core into Man sub(8)GlcNAc sub(2) isomer B, but failed to process a Man sub(5)GlcNAc sub(2)-Asn N-oligosaccharide. These properties are similar to those displayed by MNS1 purified from C. albicans membranes and strongly suggest that the enzyme is an a1,2-mannosidase that is localised to the endoplasmic reticulum and involved in the processing of N-linked mannans. Polyclonal antibodies specifically raised against recombinant MNS1 also immunoreacted with the soluble a1,2-mannosidases E-I and E-II, indicating that MNS1 could share structural similarities with both soluble enzymes. Due to the high degree of similarity between the members of family 47, it is conceivable that these antibodies may recognise a1,2-mannosidases in other biological systems as well.
ISSN:0074-0276