Biochemical identification of a lipoprotein with maltose-binding activity in the thermoacidophilic Gram-positive bacterium Alicyclobacillus acidocaldarius

Growth of the thermoacidophilic Gram-positive bacterium Alicyclobacillus acidocaldarius strain ATCC 27009 on maltose resulted in the increased production of a protein with apparent molecular mass of 40 kDa. By metabolic labelling with C-14-palmitic acid, the 40-kDa protein was identified as a lipoprotein. The protein exhibited maltose-binding activity at pH 3.5, as demonstrated by chromatography on cross-linked amylose. Partial amino acid sequence analysis revealed that the 40-kDa protein coresponds to the product of an open reading frame downstream from the amylase gene (amy) that displays similarity to enterobacterial maltose-binding proteins.