PDBsum entry: 1izj

Hydrolase

PDB id: 1izj

Contents

Protein chain

637 a.a. *

Metals

_CA ×3

Waters ×312

* Residue conservation analysis

PDB id:

1izj

Name:

Hydrolase

Title:

Thermoactinomyces vulgaris r-47 alpha-amylase 1 mutant enzyme f313a

Structure:

Amylase. Chain: a. Synonym: alpha-amylase i. Engineered: yes. Mutation: yes

Source:

Thermoactinomyces vulgaris. Organism_taxid: 2026. Strain: r-47. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.20Å R-factor: 0.179 R-free: 0.220

Authors:

A.Ohtaki,A.Iguchi,M.Mizuno,T.Tonozuka,Y.Sakano,S.Kamitori

Key ref:

A.Ohtaki et al. (2003). Mutual conversion of substrate specificities of Thermoactinomyces vulgaris R-47 alpha-amylases TVAI and TVAII by site-directed mutagenesis. Carbohydr Res, 338, 1553-1558. PubMed id: 12860426 DOI: 10.1016/S0008-6215(03)00219-2

Date:

03-Oct-02 Release date: 29-Jul-03

Protein chain

Q60053  (NEPU1_THEVU) -  Neopullulanase 1

Seq: 666 a.a.

Struc: 637 a.a.*

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

Enzyme reactions

• Enzyme class: E.C.3.2.1.135 - Neopullulanase.
• Reaction: Hydrolysis of pullulan to panose (6-alpha-D-glucosylmaltose).

 Gene Ontology (GO) functional annotation 

• Cellular component: extracellular region (1 term)
• Biological process: metabolic process (2 terms)
• Biochemical function: catalytic activity (7 terms)

DOI no: 10.1016/S0008-6215(03)00219-2

Carbohydr Res 338:1553-1558 (2003)

PubMed id: 12860426

Mutual conversion of substrate specificities of Thermoactinomyces vulgaris R-47 alpha-amylases TVAI and TVAII by site-directed mutagenesis.

A.Ohtaki, A.Iguchi, M.Mizuno, T.Tonozuka, Y.Sakano, S.Kamitori.

ABSTRACT

Thermoactinomyces vulgaris R-47 produces two alpha-amylases, TVAI and TVAII, differing in substrate specificity from each other. TVAI favors high-molecular-weight substrates like starch, and scarcely hydrolyzes cyclomaltooligosaccharides (cyclodextrins) with a small cavity. TVAII favors low-molecular-weight substrates like oligosaccharides, and can efficiently hydrolyze cyclodextrins with various sized cavities. To understand the relationship between the structure and substrate specificity of these enzymes, we precisely examined the roles of key residues for substrate recognition by X-ray structural and kinetic parameter analyses of mutant enzymes and successfully obtained mutants in which the substrate specificity of each enzyme is partially converted into that of another.