title: Characterization of the branching patterns of glycogen branching enzyme truncated on the N-terminus.
abstract: Truncation of 112 amino acids at the N-terminus (Nd(1-112)) changes the chain transfer pattern of the Escherichia coli glycogen branching enzyme (GBE) [Arch. Biochem. Biophys. 397 (2002) 279]. We investigated further the role of the N-terminus by engineering other truncated GBEs and analyzing the branching pattern by high-performance anion-exchange chromatography. The wild type GBE transfers mainly chains with a degree of polymerization (d.p.) of 8-14, the Nd(1-112) enzyme transfers a greater proportion of chains with higher d.p. 15-20, whereas the 63- and 83-amino acid deleted enzymes had an intermediate pattern of transferred chains (d.p. 10-20). These data showed that a progressive shortening of the N-terminus leads to a gradual increase in the length of the transferred chains, suggesting that the N-terminus provides a support for the glucan substrate during the processes of cleavage and transfer of the alpha-(1-4) glucan chains.
mesh_terms: D015061:1,4-alpha-Glucan Branching Enzyme / Q000032:analysis / Q000737:chemistry* / Q000235:genetics; D020134:Catalytic Domain; D002852:Chromatography, Ion Exchange; D019281:Dimerization; D004926:Escherichia coli / Q000201:enzymology; D011994:Recombinant Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D011994:Recombinant Proteins; D015061:1,4-alpha-Glucan Branching Enzyme