A novel thermostable branching enzyme from an extremely thermophilic bacterial species, Rhodothermus obamensis.

Published

Journal Article

A branching enzyme (EC 2.4.1.18) gene was isolated from an extremely thermophilic bacterium, Rhodothermus obamensis. The predicted protein encodes a polypeptide of 621 amino acids with a predicted molecular mass of 72 kDa. The deduced amino acid sequence shares 42-50% similarity to known bacterial branching enzyme sequences. Similar to the Bacillus branching enzymes, the predicted protein has a shorter N-terminal amino acid extension than that of the Escherichia coli branching enzyme. The deduced amino acid sequence does not appear to contain a signal sequence, suggesting that it is an intracellular enzyme. The R. obamensis branching enzyme was successfully expressed both in E. coli and a filamentous fungus, Aspergillus oryzae. The enzyme showed optimum catalytic activity at pH 6.0-6.5 and 65 degrees C. The enzyme was stable after 30 min at 80 degrees C and retained 50% of activity at 80 degrees C after 16 h. Branching activity of the enzyme was higher toward amylose than toward amylopectin. This is the first thermostable branching enzyme isolated from an extreme thermophile.

Full Text

Duke Authors

Cited Authors

  • Shinohara, ML; Ihara, M; Abo, M; Hashida, M; Takagi, S; Beck, TC

Published Date

  • December 2001

Published In

Volume / Issue

  • 57 / 5-6

Start / End Page

  • 653 - 659

PubMed ID

  • 11778874

Pubmed Central ID

  • 11778874

International Standard Serial Number (ISSN)

  • 0175-7598

Language

  • eng

Conference Location

  • Germany