This domain is at the very C-terminus of cyclo-malto-dextrinase proteins and consists of 8 beta strands, is largely globular and appears to help stabilise the acitve sites created by upstream domains, Cyc-maltodext_N Pfam:PF09087, and Alpha-amylase Pfam:PF00128. Cyclo-malto-dextrinases hydrolyse cyclodextrans to maltose and glucose and catalyse trans-glycosylation of oligosaccharides to the C3-, C4- or C6-hydroxyl groups of various acceptor sugar molecules.

1: Structure, specificity and function of cyclomaltodextrinase, a multispecific enzyme of the alpha-amylase family. Park KH, Kim TJ, Cheong TK, Kim JW, Oh BH, Svensson B; Biochim Biophys Acta. 2000;1478:165-185. PMID:10825529