PDBsum entry 5glo

Hydrolase

PDB id: 5glo

Contents

Protein chains

330 a.a.

Ligands

FUB ×2

ARA ×2

ACT

Metals

_NA ×4

Waters ×680

PDB id:

5glo

Name:

Hydrolase

Title:

Crystal structure of coxyl43, gh43 beta-xylosidase/alpha- arabinofuranosidase from a compostmicrobial metagenome in complex with l-arabinose, calcium-free form

Structure:

Glycoside hydrolase family 43. Chain: a, b. Fragment: unp residues 47-369. Synonym: beta-xylosidase / alpha-arabinofuranosidase. Engineered: yes

Source:

Uncultured bacterium. Organism_taxid: 77133. Gene: coxyl43. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Resolution:

1.80Å R-factor: 0.156 R-free: 0.175

Authors:

T.Matsuzawa,N.Kishine,Z.Fujimoto,K.Yaoi

Key ref:

T.Matsuzawa et al. (2017). Crystal structure of metagenomic β-xylosidase/ α-l-arabinofuranosidase activated by calcium. J Biochem, 162, 173-181. PubMed id: 28204531 DOI: 10.1093/jb/mvx012

Date:

12-Jul-16 Release date: 15-Mar-17

Protein chains

A0A0H5BL38  (A0A0H5BL38_9BACT) -  Glycoside hydrolase family 43 from uncultured bacterium

Seq: 369 a.a.

Struc: 330 a.a.*

* PDB and UniProt seqs differ at 7 residue positions (black crosses)

DOI no: 10.1093/jb/mvx012

J Biochem 162:173-181 (2017)

PubMed id: 28204531

Crystal structure of metagenomic β-xylosidase/ α-l-arabinofuranosidase activated by calcium.

T.Matsuzawa, S.Kaneko, N.Kishine, Z.Fujimoto, K.Yaoi.

ABSTRACT

The crystal structure of metagenomic β-xylosidase/α-l-arabinofuranosidase CoXyl43, activated by calcium ions, was determined in its apo and complexed forms with xylotriose or l-arabinose in the presence and absence of calcium. The presence of calcium ions dramatically increases the kcat of CoXyl43 for p-nitrophenyl β-d-xylopyranoside and reduces the Michaelis constant for p-nitrophenyl α-l-arabinofuranoside. CoXyl43 consists of a single catalytic domain comprised of a five-bladed β-propeller. In the presence of calcium, a single calcium ion was observed at the centre of this catalytic domain, behind the catalytic pocket. In the absence of calcium, the calcium ion was replaced with one sodium ion and one water molecule, and the positions of these cations were shifted by 1.3 Å. The histidine-319 side chain, which coordinates to the 2-hydroxyl oxygen atom of the bound xylose molecule in the catalytic pocket, also coordinates to the calcium ion, but not to the sodium ion. The calcium-dependent increase in activity appears to be caused by the structural change in the catalytic pocket induced by the tightly bound calcium ion and coordinating water molecules, and by the protonation state of glutamic acid-268, the catalytic acid of the enzyme. Our findings further elucidate the complex relationship between metal ions and glycosidases.