PDBsum entry 2wnh

Hydrolase

PDB id: 2wnh

Contents

Protein chains

399 a.a. *

Ligands

GOL ×2

Metals

_NA ×3

_MG

Waters ×771

* Residue conservation analysis

PDB id:

2wnh

Name:

Hydrolase

Title:

Crystal structure analysis of klebsiella sp asr1 phytase

Structure:

3-phytase. Chain: a, b. Fragment: residues 29-421. Engineered: yes. Mutation: yes

Source:

Klebsiella pneumoniae. Organism_taxid: 573. Strain: asr1. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008. Expression_system_variant: c41.

Resolution:

1.68Å R-factor: 0.182 R-free: 0.207

Authors:

K.Bohm,J.J.Mueller,U.Heinemann

Key ref:

K.Böhm et al. (2010). Crystal structure of Klebsiella sp. ASR1 phytase suggests substrate binding to a preformed active site that meets the requirements of a plant rhizosphere enzyme. Febs J, 277, 1284-1296. PubMed id: 20392204

Date:

09-Jul-09 Release date: 28-Apr-10

Protein chains

Q84CN9  (Q84CN9_KLEPN) -  3-phytase from Klebsiella pneumoniae

Seq: 421 a.a.

Struc: 399 a.a.*

* PDB and UniProt seqs differ at 8 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.1.3.8 - 3-phytase.
• Reaction: 1D-myo-inositol hexakisphosphate + H2O = 1D-myo-inositol 1,2,4,5,6- pentakisphosphate + phosphate

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

Febs J 277:1284-1296 (2010)

PubMed id: 20392204

Crystal structure of Klebsiella sp. ASR1 phytase suggests substrate binding to a preformed active site that meets the requirements of a plant rhizosphere enzyme.

K.Böhm, T.Herter, J.J.Müller, R.Borriss, U.Heinemann.

ABSTRACT

The extracellular phytase of the plant-associated Klebsiella sp. ASR1 is a member of the histidine-acid-phosphatase family and acts primarily as a scavenger of phosphate groups locked in the phytic acid molecule. The Klebsiella enzyme is distinguished from the Escherichia coli phytase AppA by its sequence and phytate degradation pathway. The crystal structure of the phytase from Klebsiella sp. ASR1 has been determined to 1.7 A resolution using single-wavelength anomalous-diffraction phasing. Despite low sequence similarity, the overall structure of Klebsiella phytase bears similarity to other histidine-acid phosphatases, such as E. coli phytase, glucose-1-phosphatase and human prostatic-acid phosphatase. The polypeptide chain is organized into an alpha and an alpha/beta domain, and the active site is located in a positively charged cleft between the domains. Three sulfate ions bound to the catalytic pocket of an inactive mutant suggest a unique binding mode for its substrate phytate. Even in the absence of substrate, the Klebsiella phytase is closer in structure to the E. coli phytase AppA in its substrate-bound form than to phytate-free AppA. This is taken to suggest a preformed substrate-binding site in Klebsiella phytase. Differences in habitat and substrate availability thus gave rise to enzymes with different substrate-binding modes, specificities and kinetics.