title: Expression and characterization of thermostable glycogen branching enzyme fromGeobacillus mahadiaGeo-05.
abstract: The glycogen branching enzyme (EC 2.4.1.18), which catalyses the formation ofα-1,6-glycosidic branch points in glycogen structure, is often used to enhance the nutritional value and quality of food and beverages. In order to be applicable in industries, enzymes that are stable and active at high temperature are much desired. Using genome mining, the nucleotide sequence of the branching enzyme gene (glgB) was extracted from theGeobacillus mahadiaGeo-05 genome sequence provided by the Malaysia Genome Institute. The size of the gene is 2013 bp, and the theoretical molecular weight of the protein is 78.43 kDa. The gene sequence was then used to predict the thermostability, function and the three dimensional structure of the enzyme. The gene was cloned and overexpressed inE. colito verify the predicted result experimentally. The purified enzyme was used to study the effect of temperature and pH on enzyme activity and stability, and the inhibitory effect by metal ion on enzyme activity. This thermostable glycogen branching enzyme was found to be most active at 55 °C, and the half-life at 60 °C and 70 °C was 24 h and 5 h, respectively. From this research, a thermostable glycogen branching enzyme was successfully isolated fromGeobacillus mahadiaGeo-05 by genome mining together with molecular biology technique.
authors.affiliation: Faculty of Science, Universiti Putra Malaysia , Serdang , Selangor , Malaysia.
authors.forename: Nur Syazwani
authors.initials: NS
authors.lastname: Mohtar
authors.affiliation: Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; Malaysia Genome Institute, Kajang, Selangor, Malaysia.
authors.forename: Mohd Basyaruddin
authors.initials: MB
authors.lastname: Abdul Rahman
authors.affiliation: Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia , Serdang , Selangor , Malaysia.
authors.forename: Raja Noor Zaliha
authors.initials: RN
authors.lastname: Raja Abd Rahman
authors.affiliation: Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia , Serdang , Selangor , Malaysia.
authors.forename: Thean Chor
authors.initials: TC
authors.lastname: Leow
authors.affiliation: Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia , Serdang , Selangor , Malaysia.
authors.forename: Abu Bakar
authors.initials: AB
authors.lastname: Salleh
authors.affiliation: Malaysia Genome Institute , Kajang , Selangor , Malaysia.
authors.forename: Mohd Noor
authors.initials: MN
authors.lastname: Mat Isa
keywords: 1-4-alpha-glucan branching enzyme; Genome mining; Geobacillus sp; Glycogen branching enzyme; His-patch thioredoxin