Document Detail


Role of C-terminal acidic cluster in stabilization of heme spin state of ascorbate peroxidase from Leishmania major.
MedLine Citation:
PMID:  20060805     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Architecture of hemoprotein is solely responsible for different nature of heme coordination. Here we report that substitution of the acidic surface residue Glu226 to Ala in ascorbate peroxidase from Leishmania major alters the 5 coordinate high spin (5cHS) to a 6 coordinate low spin (6cLS) form at pH 7.5. Using UV-visible spectrophotometry, we show that the sixth ligand of heme in Glu226Ala at pH 7.5 is hydroxo. When the pH is decreased to 5.5, a new species of Glu226Ala appeared that had a spectrum characteristic of a 6cHS derivative. Stopped flow spectrophotometric techniques revealed that characteristics of Compound I was not seen in the Glu226Ala in presence of H(2)O(2). Similarly guaiacol, ascorbate and ferrocytochrome c oxidation rate was 10(3) orders less for the Glu226Ala mutants compared to the wild type. These data suggested that surface acidic residue Glu226 might play role in proper maintenance of active site conformation.
Authors:
Rajesh K Yadav; Subhankar Dolai; Swati Pal; Subrata Adak
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-01-12
Journal Detail:
Title:  Archives of biochemistry and biophysics     Volume:  495     ISSN:  1096-0384     ISO Abbreviation:  Arch. Biochem. Biophys.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-03-01     Completed Date:  2010-04-01     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0372430     Medline TA:  Arch Biochem Biophys     Country:  United States    
Other Details:
Languages:  eng     Pagination:  129-35     Citation Subset:  IM    
Copyright Information:
2010 Elsevier Inc. All rights reserved.
Affiliation:
Indian Institute of Chemical Biology, Council of Scientific and Industrial Research, Kolkata, India.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Catalytic Domain
Circular Dichroism
Heme / chemistry*
Hydrogen Peroxide / metabolism
Kinetics
Leishmania major / enzymology*
Models, Molecular
Molecular Sequence Data
Mutagenesis, Site-Directed
Peroxidases / chemistry*,  genetics*,  metabolism
Sequence Alignment
Spectrophotometry, Ultraviolet
Structural Homology, Protein
Chemical
Reg. No./Substance:
14875-96-8/Heme; 7722-84-1/Hydrogen Peroxide; EC 1.11.1.-/Peroxidases; EC 1.11.1.11/ascorbate peroxidase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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