Aspergillus niger van Tieghem mannosylation: polyprenylphosphate mannosyltransferase specificity

Area of Science:

• Biochemistry
• Enzymology
• Microbiology

Background:

• Microsomes from Aspergillus niger possess enzymatic activity.
• Polyprenylphosphate is involved in glycosylation pathways.

Purpose of the Study:

• To characterize the enzyme responsible for mannose transfer in Aspergillus niger.
• To investigate the substrate specificity of the mannose transfer enzyme.

Main Methods:

• Enzyme assays using GDP-mannose as the sugar donor.
• Testing various lengths of polyprenylphosphates (C15-C120) as acceptors.
• Utilizing liposome fusion techniques to present acceptors to the enzyme.

Main Results:

• The enzyme efficiently transfers mannose from GDP-mannose.
• All tested polyprenylphosphates (C15-C120) served as acceptors, with the exception of retinylphosphate.
• The enzyme exhibited strict specificity for both the nucleoside diphosphate sugar and the polyprenylphosphate base.

Conclusions:

• Aspergillus niger possesses a specific mannose transfer enzyme.
• This enzyme plays a role in the synthesis of polyprenylmannose derivatives.
• Understanding this enzyme's specificity is crucial for studying glycosylation in fungi.