PDBsum entry 5f7c

Hydrolase

PDB id: 5f7c

Contents

Protein chains

625 a.a.

Waters ×67

PDB id:

5f7c

Name:

Hydrolase

Title:

Crystal structure of family 31 alpha-glucosidase (bt_0339) from bacteroides thetaiotaomicron

Structure:

Alpha-glucosidase. Chain: a, b, c, d. Engineered: yes

Source:

Bacteroides thetaiotaomicron. Organism_taxid: 226186. Strain: atcc 29148 / dsm 2079 / nctc 10582 / e50 / vpi-5482. Gene: bt_0339. Expressed in: escherichia coli 'bl21-gold(de3)plyss ag'. Expression_system_taxid: 866768

Resolution:

2.60Å R-factor: 0.304 R-free: 0.349

Authors:

M.M.Chaudet,D.R.Rose

Key ref:

M.M.Chaudet and D.R.Rose (2016). Suggested alternative starch utilization system from the human gut bacterium Bacteroides thetaiotaomicron. Biochem Cell Biol, 94, 241-246. PubMed id: 27093479 DOI: 10.1139/bcb-2016-0002

Date:

07-Dec-15 Release date: 17-Feb-16

Protein chains

Q8AAX3  (Q8AAX3_BACTN) -  Alpha-glucosidase from Bacteroides thetaiotaomicron (strain ATCC 29148 / DSM 2079 / JCM 5827 / CCUG 10774 / NCTC 10582 / VPI-5482 / E50)

Seq: 748 a.a.

Struc: 625 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.2.1.20 - alpha-glucosidase.
• Reaction: Hydrolysis of terminal, non-reducing 1,4-linked D-glucose residues with release of D-glucose.

DOI no: 10.1139/bcb-2016-0002

Biochem Cell Biol 94:241-246 (2016)

PubMed id: 27093479

Suggested alternative starch utilization system from the human gut bacterium Bacteroides thetaiotaomicron.

M.M.Chaudet, D.R.Rose.

ABSTRACT

The human digestive system is host to a highly populated ecosystem of bacterial species that significantly contributes to our assimilation of dietary carbohydrates. Bacteroides thetaiotaomicron is a member of this ecosystem, and participates largely in the role of the gut microbiome by breaking down dietary complex carbohydrates. This process of acquiring glycans from the colon lumen is predicted to rely on the mechanisms of proteins that are part of a classified system known as polysaccharide utilization loci (PUL). These loci are responsible for binding substrates at the cell outer membrane, internalizing them, and then hydrolyzing them within the periplasm into simple sugars. Here we report our investigation into specific components of a PUL, and suggest an alternative starch utilization system in B. thetaiotaomicron. Our analysis of an outer membrane binding protein, a SusD homolog, highlights its contribution to this PUL by acquiring starch-based sugars from the colon lumen. Through our structural characterization of two Family GH31 α-glucosidases, we reveal the flexibility of this bacterium with respect to utilizing a range of starch-derived glycans with an emphasis on branched substrates. With these results we demonstrate the predicted function of a gene locus that is capable of contributing to starch hydrolysis in the human colon.