Glyco_trans_A_1 is family of found predominantly at the N-terminus of various prokaryotic alpha-glucosyltransferases. According to whether the domain exists as a whole molecule or as a half molecule determines the number of sugar residues that the molecule transfers. Two-domain proteins are processive in that they transfer more than one sugar residue, processively; single domain proteins transfer just one sugar moiety [1,2,3].

1: Multidomain architecture of beta-glycosyl transferases: implications for mechanism of action. Saxena IM, Brown RM Jr, Fevre M, Geremia RA, Henrissat B; J Bacteriol. 1995;177:1419-1424. PMID:7883697

2: A molecular chaperone mediates a two-protein enzyme complex and glycosylation of serine-rich streptococcal adhesins. Wu R, Wu H; J Biol Chem. 2011;286:34923-34931. PMID:21862581