5JBD

4,6-alpha-glucanotransferase GTFB from Lactobacillus reuteri 121

Summary for 5JBD

• Entry DOI: 10.2210/pdb5jbd/pdb
• Descriptor: Inactive glucansucrase, CALCIUM ION, ACETATE ION, ... (7 entities in total)
• Functional Keywords: 4, 6-alpha-glucanotransferase, starch conversion, gh70, transferase
• Biological source: Lactobacillus reuteri
• Total number of polymer chains: 2
• Total formula weight: 200757.44

Authors

Pijning, T.,Dijkstra, B.W.,Bai, Y.,Gangoiti-Munecas, J.,Dijkhuizen, L. (deposition date: 2016-04-13, release date: 2017-01-18, Last modification date: 2024-01-10)

Primary citation

Bai, Y.,Gangoiti, J.,Dijkstra, B.W.,Dijkhuizen, L.,Pijning, T.
Crystal Structure of 4,6-alpha-Glucanotransferase Supports Diet-Driven Evolution of GH70 Enzymes from alpha-Amylases in Oral Bacteria.
Structure, 25:231-242, 2017

PubMed Abstract: Food processing and refining has dramatically changed the human diet, but little is known about whether this affected the evolution of enzymes in human microbiota. We present evidence that glycoside hydrolase family 70 (GH70) glucansucrases from lactobacilli, synthesizing α-glucan-type extracellular polysaccharides from sucrose, likely evolved from GH13 starch-acting α-amylases, via GH70 4,6-α-glucanotransferases. The crystal structure of a 4,6-α-glucanotransferase explains the mode of action and unique product specificity of these enzymes. While the α-amylase substrate-binding scaffold is retained, active-site loops adapted to favor transglycosylation over hydrolysis; the structure also gives clues as to how 4,6-α-glucanotransferases may have evolved further toward sucrose utilization instead of starch. Further supported by genomic, phylogenetic, and in vivo studies, we propose that dietary changes involving starch (and starch derivatives) and sucrose intake were critical factors during the evolution of 4,6-α-GTs and glucansucrases from α-amylases, allowing oral bacteria to produce extracellular polymers that contribute to biofilm formation from different substrates.

PubMed: 28065507
DOI: 10.1016/j.str.2016.11.023

Experimental method

X-RAY DIFFRACTION (1.8 Å)