A crystallographic study of Cys69Ala flavodoxin II fromAzotobacter vinelandii: Structural determinants of redox potential

Autor: Carlo P. M. van Mierlo, Bauke W. Dijkstra, Sharmini Alagaratnam, Gerard W. Canters, Gian Luigi Rossi, Tjaard Pijning, Walter van Dongen, Willem J. H. van Berkel, Gertie van Pouderoyen, Davide Cavazzini
Rok vydání: 2005
Předmět:
Models
Molecular
Protein Folding
Semiquinone
Flavin Mononucleotide
Protein Conformation
Flavodoxin
Stereochemistry
desulfovibrio-vulgaris hildenborough
Molecular Sequence Data
Glycine
Biochemie
Flavin mononucleotide
Crystallography
X-Ray
Biochemistry
Article
anacystis-nidulans
chemistry.chemical_compound
FMN binding
Protein structure
megasphaera-elsdenii
Leucine
310 helix
oxidized flavodoxin
Molecular replacement
Amino Acid Sequence
Cysteine
Molecular Biology
VLAG
Azotobacter vinelandii
Alanine
Binding Sites
Sequence Homology
Amino Acid
biology
Chemistry
Tryptophan
mononucleotide binding-site
Hydrogen Bonding
electron-transfer
long-chain flavodoxin
biology.organism_classification
Crystallography
Structural Homology
Protein
biology.protein
flavin-binding
oxidation-reduction potentials
crystal-structures
Zdroj: Protein Science, 14(9), 2284-2295
Protein Science 14 (2005) 9
Protein Science, 14(9), 2284-2295. WILEY-BLACKWELL
ISSN: 1469-896X
0961-8368
DOI: 10.1110/ps.051582605
Popis: Flavodoxin II from Azotobacter vinelandii is a "long-chain" flavodoxin and has one of the lowest E(1) midpoint potentials found within the flavodoxin family. To better understand the relationship between structural features and redox potentials, the oxidized form of the C69A mutant of this flavodoxin was crystallized and its three-dimensional structure determined to a resolution of 2.25 A by molecular replacement. Its overall fold is similar to that of other flavodoxins, with a central five-stranded parallel P-sheet flanked on either side by alpha-helices. An eight-residue insertion, compared with other long-chain flavodoxins, forms a short 310 helix preceding the start of the alpha(3) helix. The flavin mononucleotide (FMN) cofactor is flanked by a leucine on its re face instead of the more conserved tryptophan, resulting in a more solvent-accessible FMN binding site and stabilization of the hydroquirione (hq) state. In particular the absence of a hydrogen bond to the N5 atom of the oxidized FMN was identified, which destabilizes the ox form, as well as an exceptionally large patch of acidic residues in the vicinity of the FMN N1 atom, which destabilizes the hq form. It is also argued that the presence of a Gly at position 58 in the sequence stabilizes the serniquinone (sq) form, as a result, raising the E(2) value in particular.
Databáze: OpenAIRE
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