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Memórias do Instituto Oswaldo Cruz
Fundação Oswaldo Cruz, Fiocruz
ISSN: 1678-8060
EISSN: 1678-8060
Vol. 105, No. 1, 2010, pp. 79-85
Bioline Code: oc10012
Full paper language: English
Document type: Research Article
Document available free of charge

Memórias do Instituto Oswaldo Cruz, Vol. 105, No. 1, 2010, pp. 79-85

 en Purification and biochemical characterisation of endoplasmic reticulum α1,2-mannosidase from Sporothrix schenckii check for this species in other resources
Mora-Montes, Héctor M; Robledo-Ortiz, Claudia I; González-Sánchez, Laura C; López-Esparza, Adolfo; López-Romero, Everardo & Flores-Carreón, Arturo

Abstract

Alpha 1,2-mannosidases from glycosyl hydrolase family 47 participate in N-glycan biosynthesis. In filamentous fungi and mammalian cells, α1,2-mannosidases are present in the endoplasmic reticulum (ER) and Golgi complex and are required to generate complex N-glycans. However, lower eukaryotes such Saccharomyces cerevisiae check for this species in other resources contain only one α1,2-mannosidase in the lumen of the ER and synthesise high-mannose N-glycans. Little is known about the N-glycan structure and the enzyme machinery involved in the synthesis of these oligosaccharides in the dimorphic fungus Sporothrix schenckii check for this species in other resources . Here, a membrane-bound α-mannosidase from S. schenckii was solubilised using a high-temperature procedure and purified by conventional methods of protein isolation. Analytical zymograms revealed a polypeptide of 75 kDa to be responsible for enzyme activity and this purified protein was recognised by anti-α1,2-mannosidase antibodies. The enzyme hydrolysed Man9GlcNAc2 into Man8GlcNAc2 isomer B and was inhibited preferentially by 1-deoxymannojirimycin. This α1,2-mannosidase was localised in the ER, with the catalytic domain within the lumen of this compartment. These properties are consistent with an ER-localised α1,2-mannosidase of glycosyl hydrolase family 47. Our results also suggested that in contrast to other filamentous fungi, S. schenckii lacks Golgi α1,2-mannosidases and therefore, the processing of N-glycans by α1,2-mannosidases is similar to that present in lower eukaryotes.

Keywords
α1,2-mannosidase - N-glycosylation - Sporothrix schenckii - endoplasmic reticulum

 
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