Title :

Characterization of substrate and product specificity of the purified recombinant glycogen branching enzyme of Rhodothermus obamensis

Author(s) :

Roussel, Xavier [Auteur]
Lancelon-Pin, Christine [Auteur]
Viksø-Nielsen, Anders [Auteur]
Rolland-Sabaté, Agnès [Auteur]
Grimaud, Florent [Auteur]
Potocki-Véronèse, Gabrielle [Auteur]
Buléon, Alain [Auteur]
Putaux, Jean-Luc [Auteur]
D'hulst, Christophe [Auteur]
Unité de Glycobiologie Structurale et Fonctionnelle (UGSF) - UMR 8576

Journal title :

Biochimica et biophysica acta

Abbreviated title :

Biochim. Biophys. Acta

Volume number :

1830

Pages :

2167-2177

Publication date :

2013-01

ISSN :

0006-3002

English keyword(s) :

Substrate Specificity
1,4-alpha-Glucan Branching Enzyme
Catalysis
Rhodothermus
Bacterial Proteins
Enzyme Stability

HAL domain(s) :

Chimie/Chimie théorique et/ou physique

English abstract : [en]

BACKGROUND: Glycogen and starch branching enzymes catalyze the formation of α(1→6) linkages in storage polysaccharides by rearrangement of preexisting α-glucans. This reaction occurs through the cleavage of α(1→4) linkage ...
Show more >BACKGROUND: Glycogen and starch branching enzymes catalyze the formation of α(1→6) linkages in storage polysaccharides by rearrangement of preexisting α-glucans. This reaction occurs through the cleavage of α(1→4) linkage and transfer in α(1→6) of the fragment in non-reducing position. These enzymes define major elements that control the structure of both glycogen and starch. METHODS: The kinetic parameters of the branching enzyme of Rhodothermus obamensis (RoBE) were established after in vitro incubation with different branched or unbranched α-glucans of controlled structure. RESULTS: A minimal chain length of ten glucosyl units was required for the donor substrate to be recognized by RoBE that essentially produces branches of DP 3-8. We show that RoBE preferentially creates new branches by intermolecular mechanism. Branched glucans define better substrates for the enzyme leading to the formation of hyper-branched particles of 30-70nm in diameter (dextrins). Interestingly, RoBE catalyzes an additional α-4-glucanotransferase activity not described so far for a member of the GH13 family. CONCLUSIONS: RoBE is able to transfer α(1→4)-linked-glucan in C4 position (instead of C6 position for the branching activity) of a glucan to create new α(1→4) linkages yielding to the elongation of linear chains subsequently used for further branching. This result is a novel case for the thin border that exists between enzymes of the GH13 family. GENERAL SIGNIFICANCE: This work reveals the original catalytic properties of the thermostable branching enzyme of R. obamensis. It defines new approach to produce highly branched α-glucan particles in vitro.Show less >

Language :

Anglais

Administrative institution(s) :

CNRS
Université de Lille

Collections :

• Unité de Glycobiologie Structurale et Fonctionnelle (UGSF) - UMR 8576

Research team(s) :

Plant Storage Polysaccharides

Submission date :

2020-02-12T15:11:46Z