Truncation of the amino terminus of branching enzyme changes its chain transfer pattern.
Arch Biochem Biophys
; 397(2): 279-85, 2002 Jan 15.
Article
em En
| MEDLINE
| ID: mdl-11795883
ABSTRACT
Previous work has reported the production of an Escherichia coli branching enzyme with a 112-residue deletion at the amino terminal by limited proteolysis. Here, we study the chain transfer pattern of this enzyme. Gel-permeation chromatography of in vitro branched amylose shows that the truncated branching enzyme transfers fewer short chains (degree of polymerization [d.p.] <20) and a greater proportion of intermediate size chains (d.p. 30-90) than the native enzyme. High-performance anion-exchange chromatography (HPAEC) of the branching limited alpha-glucan product indicates that the truncated branching enzyme transfers a smaller proportion of chains with d.p. 4-11 and more chains longer than d.p. 12. Also, the genes encoding native or truncated branching enzyme were individually expressed in a branching enzyme-deficient mutant, AC71 (glgB(-)). By HPAEC analysis of the purified alpha-glucans we find that truncated branching enzyme transfers fewer chains of d.p. 5-11 and more chains longer than d.p. 12 relative to the full-length enzyme. These observations allow us to conclude that truncation of the amino-terminal domain has altered the branching pattern of the enzyme. Our results are consistent with the construction of hybrid branching enzymes from the maize isoforms.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Escherichia coli
/
Enzima Ramificadora de 1,4-alfa-Glucana
/
Amilose
Idioma:
En
Revista:
Arch Biochem Biophys
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos