Molecular Characterization and Expression of a Novel Alcohol Oxidase from Aspergillus terreus MTCC6324

The alcohol oxidase (AOx) cDNA from Aspergillus terreus MTCC6324 with an open reading frame (ORF) of 2001 bp was constructed from n-hexadecane induced cells and expressed in Escherichia coli with a yield of,4.2 mg protein g21 wet cell. The deduced amino acid sequences of recombinant rAOx showed maximum structural homology with the chain B of aryl AOx from Pleurotus eryngii. A functionally active AOx was achieved by incubating the apo-AOx with flavin adenine dinucleotide (FAD) for,80 h at 16uC and pH 9.0. The isoelectric point and mass of the apo-AOx were found to be 6.560.1 and,74 kDa, respectively. Circular dichroism data of the rAOx confirmed its ordered structure. Docking studies with an ab-initio protein model demonstrated the presence of a conserved FAD binding domain with an active substrate binding site. The rAOx was specific for aryl alcohols and the order of its substrate preference was 4-methoxybenzyl alcohol.3-methoxybenzyl alcohol.3, 4-dimethoxybenzyl alcohol. benzyl alcohol. A significantly high aggregation to,1000 nm (diameter) and catalytic efficiency (kcat/Km) of 7829.5 min 21 mM21 for 4-methoxybenzyl alcohol was also demonstrated for rAOx. The results infer the novelty of the AOx and its potential biocatalytic application