The synthesis of β-mannoside and β-mannosamine poses one of the greatest challenges to the carbohydrate chemists,because the mechanism of forming mannoside or mannosamine,either neighboring group participation method or non-neighboring group participation method,leads predominately to the α-anomer.

A plasmid ,pMD-18Tman2XcmI is developed,the plasmid is constructed by cloning an Xcm?I cassette with mannanase gene (man 1?101?bp long) between two Xcm?I restriction sites into pMD-18T.

Condensation mechanism of aminoglucomannan with plasmid DNA;