ISDA

Entry Detail

PDB ID:

1WO2

Keywords:

Title:

Crystal structure of the pig pancreatic alpha-amylase complexed with malto-oligosaacharides under the effect of the chloride ion

Biological Source:

Source Organism:

Sus scrofa

Host Organism:

Escherichia coli

PDB Version:

Deposition Date:

2004-08-11

Release Date:

2005-03-15

Method Details:

Experimental Method:

X-RAY DIFFRACTION

Resolution:

2.01 Å

R-Value Free:

0.18

R-Value Work:

0.15

R-Value Observed:

0.15

Space Group:

P 21 21 21

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Macromolecular Entities

Protein Blast

Polymer Type:polypeptide(L)
Description:Alpha-amylase, pancreatic
Mutations:Q16PCA
Chain IDs:A
Chain Length:496
Number of Molecules:1
Biological Source: Sus scrofa

UniProt ID:P00690 Pfam ID:PF00128, PF02806 EC:3.2.1.1

Modified Residue

Compound ID	Chain ID	Parent Comp ID	Details	2D Image
PCA	A	GLN	PYROGLUTAMIC ACID

Ligand Molecules

EDO

Peptide-like Molecules

PRD_900018

PRD_900065

Primary Citation

Molecular Basis of the Effects of Chloride Ion on the Acid-Base Catalyst in the Mechanism of Pancreatic alpha-Amylase

Qian, M, Ajandouz, E.H, Payan, F, Nahoum, V, Qian, M, Nahoum, V, Bonicel, J, Bischoff, H, Henrissat, B, Payan, F, Payan, F, Qian, M.Show

Biochemistry 44 3194 3201 (2005)

PMID: 15736930 DOI: 10.1021/bi048201t

Abstact

Pig pancreatic alpha-amylase (PPA), an enzyme belonging to the alpha-amylase family, is involved in the degradation of starch. Like some other members of this family, PPA requires chloride to reach maximum activity levels. To further explain the mechanism of chloride activation, a crystal of wild-type PPA soaked with maltopentaose using a chloride-free buffer was analyzed by X-ray crystallography. A conspicuous reorientation of the acid/base catalyst Glu233 residue was found to occur. The structural results, along with kinetic data, show that the acid/base catalyst is maintained in the active site, in an optimum position, pointing toward the scissile bond-atom, due to the presence of chloride ions. The present study therefore explains the mechanism of PPA activation by chloride ions.

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