PDBsum entry: 3bkq

Isomerase

PDB id: 3bkq

Contents

Protein chain

458 a.a. *

Ligands

G1P

Metals

_ZN

Waters ×204

* Residue conservation analysis

PDB id:

3bkq

Name:

Isomerase

Title:

Structure of the p368g mutant of pmm/pgm in complex with its

Structure:

Phosphomannomutase/phosphoglucomutase. Chain: x. Synonym: pmm/pgm. Engineered: yes. Mutation: yes

Source:

Pseudomonas aeruginosa. Strain: pao1. Gene: algc. Expressed in: escherichia coli.

Resolution:

2.05Å R-factor: 0.220 R-free: 0.249

Authors:

R.Mehra-Chaudhary,L.J.Beamer

Key ref:

A.M.Schramm et al. (2008). Backbone flexibility, conformational change, and catalysis in a phosphohexomutase from Pseudomonas aeruginosa. Biochemistry, 47, 9154-9162. PubMed id: 18690721 DOI: 10.1021/bi8005219

Date:

07-Dec-07 Release date: 09-Sep-08

Protein chain

P26276  (ALGC_PSEAE) -  Phosphomannomutase/phosphoglucomutase

Seq: 463 a.a.

Struc: 458 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class 1: E.C.5.4.2.2 - Phosphoglucomutase.
• Pathway: UDP-glucose, UDP-galactose and UDP-glucuronate Biosynthesis
• Reaction: Alpha-D-glucose 1-phosphate = alpha-D-glucose 6-phosphate

Alpha-D-glucose 1-phosphate (Bound ligand (Het Group name = G1P) corresponds exactly) = alpha-D-glucose 6-phosphate

• Enzyme class 2: E.C.5.4.2.8 - Phosphomannomutase.

Pathway:

• Reaction: Alpha-D-mannose 1-phosphate = D-mannose 6-phosphate

Alpha-D-mannose 1-phosphate (Bound ligand (Het Group name = G1P) corresponds exactly) = D-mannose 6-phosphate

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

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

 Gene Ontology (GO) functional annotation 

• Biological process: metabolic process (4 terms)
• Biochemical function: catalytic activity (7 terms)

reference

DOI no: 10.1021/bi8005219

Biochemistry 47:9154-9162 (2008)

PubMed id: 18690721

Backbone flexibility, conformational change, and catalysis in a phosphohexomutase from Pseudomonas aeruginosa.

A.M.Schramm, R.Mehra-Chaudhary, C.M.Furdui, L.J.Beamer.

ABSTRACT

The enzyme phosphomannomutase/phosphoglucomutase (PMM/PGM) from the bacterium Pseudomonas aeruginosa is involved in the biosynthesis of several complex carbohydrates, including alginate, lipopolysaccharide, and rhamnolipid. Previous structural studies of this protein have shown that binding of substrates produces a rotation of the C-terminal domain, changing the active site from an open cleft in the apoenzyme into a deep, solvent inaccessible pocket where phosphoryl transfer takes place. We report herein site-directed mutagenesis, kinetic, and structural studies in examining the role of residues in the hinge between domains 3 and 4, as well as residues that participate in enzyme-substrate contacts and help form the multidomain "lid" of the active site. We find that the backbone flexibility of residues in the hinge region (e.g., mutation of proline to glycine/alanine) affects the efficiency of the reaction, decreasing k cat by approximately 10-fold and increasing K m by approximately 2-fold. Moreover, thermodynamic analyses show that these changes are due primarily to entropic effects, consistent with an increase in the flexibility of the polypeptide backbone leading to a decreased probability of forming a catalytically productive active site. These results for the hinge residues contrast with those for mutants in the active site of the enzyme, which have profound effects on enzyme kinetics (10 (2)-10 (3)-fold decrease in k cat/ K m) and also show substantial differences in their thermodynamic parameters relative to those of the wild-type (WT) enzyme. These studies support the concept that polypeptide flexibility in protein hinges may evolve to optimize and tune reaction rates.