Document Detail

Modulation of the enzymatic efficiency of ferredoxin-NADP(H) reductase by the amino acid volume around the catalytic site.
MedLine Citation:
PMID:  18279389     Owner:  NLM     Status:  MEDLINE    
Ferredoxin (flavodoxin)-NADP(H) reductases (FNRs) are ubiquitous flavoenzymes that deliver NADPH or low-potential one-electron donors (ferredoxin, flavodoxin, adrenodoxin) to redox-based metabolic reactions in plastids, mitochondria and bacteria. Plastidic FNRs are quite efficient reductases. In contrast, FNRs from organisms possessing a heterotrophic metabolism or anoxygenic photosynthesis display turnover numbers 20- to 100-fold lower than those of their plastidic and cyanobacterial counterparts. Several structural features of these enzymes have yet to be explained. The residue Y308 in pea FNR is stacked nearly parallel to the re-face of the flavin and is highly conserved amongst members of the family. By computing the relative free energy for the lumiflavin-phenol pair at different angles with the relative position found for Y308 in pea FNR, it can be concluded that this amino acid is constrained against the isoalloxazine. This effect is probably caused by amino acids C266 and L268, which face the other side of this tyrosine. Simple and double FNR mutants of these amino acids were obtained and characterized. It was observed that a decrease or increase in the amino acid volume resulted in a decrease in the catalytic efficiency of the enzyme without altering the protein structure. Our results provide experimental evidence that the volume of these amino acids participates in the fine-tuning of the catalytic efficiency of the enzyme.
Matías A Musumeci; Adrián K Arakaki; Daniela V Rial; Daniela L Catalano-Dupuy; Eduardo A Ceccarelli
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-02-12
Journal Detail:
Title:  The FEBS journal     Volume:  275     ISSN:  1742-464X     ISO Abbreviation:  FEBS J.     Publication Date:  2008 Mar 
Date Detail:
Created Date:  2008-03-05     Completed Date:  2008-05-07     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  101229646     Medline TA:  FEBS J     Country:  England    
Other Details:
Languages:  eng     Pagination:  1350-66     Citation Subset:  IM    
Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario (IBR), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Argentina.
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MeSH Terms
Amino Acid Substitution
Amino Acids / chemistry,  genetics
Catalytic Domain / genetics
Crystallography, X-Ray
Ferredoxin-NADP Reductase / chemistry*,  genetics
Flavin-Adenine Dinucleotide / analysis,  chemistry
Hot Temperature
Protein Conformation
Protein Folding
Protein Structure, Secondary
Reg. No./Substance:
0/Amino Acids; 146-14-5/Flavin-Adenine Dinucleotide; EC Reductase

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