This domain is found at the C-terminal of various fungal alpha-amylase proteins [1]. It has been identified as a secondary binding site, which might be part of a starch interaction site [2]. It has a beta- sandwich fold comprising an antiparallel beta-sheet with eight strands [2,3].

1: Structure of the Aspergillus oryzae alpha-amylase complexed with the inhibitor acarbose at 2.0 A resolution. Brzozowski AM, Davies GJ; Biochemistry. 1997;36:10837-10845. PMID:9283074

2: Structural and Functional Characterization of Three Novel Fungal Amylases with Enhanced Stability and pH Tolerance. Roth C, Moroz OV, Turkenburg JP, Blagova E, Waterman J, Ariza A, Ming L, Tianqi S, Andersen C, Davies GJ, Wilson KS; Int J Mol Sci. 2019; [Epub ahead of print] PMID:31623309

3: A novel multifunctional alpha-amylase from the thermophilic fungus Malbranchea cinnamomea: biochemical characterization and three-dimensional structure. Han P, Zhou P, Hu S, Yang S, Yan Q, Jiang Z; Appl Biochem Biotechnol. 2013;170:420-435. PMID:23536251