PDBsum entry: 3bsg

Hydrolase

PDB id: 3bsg

Contents

Protein chain

404 a.a. *

Metals

_CA ×3

Waters ×630

* Residue conservation analysis

PDB id:

3bsg

Name:

Hydrolase

Title:

Barley alpha-amylase isozyme 1 (amy1) h395a mutant

Structure:

Alpha-amylase type a isozyme. Chain: a. Synonym: alpha-amylase isozyme 1, 1,4-alpha-d- glucan glucanohydrolase, amy1, low pi alpha-amylase. Engineered: yes. Mutation: yes

Source:

Hordeum vulgare. Barley. Organism_taxid: 4513. Expressed in: pichia pastoris. Expression_system_taxid: 4922.

Resolution:

1.95Å R-factor: 0.211 R-free: 0.266

Authors:

N.Aghajari,X.Robert,R.Haser

Key ref:

M.M.Nielsen et al. (2008). Multi-site substrate binding and interplay in barley alpha-amylase 1. Febs Lett, 582, 2567-2571. PubMed id: 18588886 DOI: 10.1016/j.febslet.2008.06.027

Date:

24-Dec-07 Release date: 26-Aug-08

Protein chain

P00693  (AMY1_HORVU) -  Alpha-amylase type A isozyme

Seq: 438 a.a.

Struc: 404 a.a.*

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

Enzyme reactions

• Enzyme class: E.C.3.2.1.1 - Alpha-amylase.
• Reaction: Endohydrolysis of 1,4-alpha-glucosidic linkages in oligosaccharides and polysaccharides.

 Gene Ontology (GO) functional annotation 

• Cellular component: extracellular region (2 terms)
• Biological process: metabolic process (2 terms)
• Biochemical function: catalytic activity (7 terms)

DOI no: 10.1016/j.febslet.2008.06.027

Febs Lett 582:2567-2571 (2008)

PubMed id: 18588886

Multi-site substrate binding and interplay in barley alpha-amylase 1.

M.M.Nielsen, E.S.Seo, S.Bozonnet, N.Aghajari, X.Robert, R.Haser, B.Svensson.

ABSTRACT

Certain starch hydrolases possess secondary carbohydrate binding sites outside of the active site, suggesting that multi-site substrate interactions are functionally significant. In barley alpha-amylase both Tyr380, situated on a remote non-catalytic domain, and Tyr105 in subsite -6 of the active site cleft are principal carbohydrate binding residues. The dual active site/secondary site mutants Y105A/Y380A and Y105A/Y380M show that each of Tyr380 and Tyr105 is important, albeit not essential for binding, degradation, and multiple attack on polysaccharides, while Tyr105 predominates in oligosaccharide hydrolysis. Additional delicate structure/function relationships of the secondary site are uncovered using Y380A/H395A, Y380A, and H395A AMY1 mutants.