1F5B

CRYSTAL STRUCTURE OF F2H FERREDOXIN 1 MUTANT FROM AZOTOBACTER VINELANDII AT 1.75 ANGSTROM RESOLUTION

Summary for 1F5B

• Entry DOI: 10.2210/pdb1f5b/pdb
• Related: 1D3W 1F5C 1FDD 6FDR 7FDR
• Descriptor: FERREDOXIN 1, FE3-S4 CLUSTER, IRON/SULFUR CLUSTER, ... (4 entities in total)
• Functional Keywords: beta-sheet, protein monomer, iron sulfur protein, ferredoxin, electron transport
• Biological source: Azotobacter vinelandii
• Total number of polymer chains: 1
• Total formula weight: 12697.94

Authors

Chen, K.,Bonagura, C.A.,Tilley, G.J.,Jung, Y.S.,Armstrong, F.A.,Stout, C.D.,Burgess, B.K. (deposition date: 2000-06-13, release date: 2000-06-28, Last modification date: 2024-02-07)

Primary citation

Chen, K.,Bonagura, C.A.,Tilley, G.J.,McEvoy, J.P.,Jung, Y.S.,Armstrong, F.A.,Stout, C.D.,Burgess, B.K.
Crystal structures of ferredoxin variants exhibiting large changes in [Fe-S] reduction potential.
Nat.Struct.Biol., 9:188-192, 2002

PubMed Abstract: Elucidating how proteins control the reduction potentials (E0') of [Fe--S] clusters is a longstanding fundamental problem in bioinorganic chemistry. Two site-directed variants of Azotobacter vinelandii ferredoxin I (FdI) that show large shifts in [Fe--S] cluster E0' (100--200 mV versus standard hydrogen electrode (SHE)) have been characterized. High resolution X-ray structures of F2H and F25H variants in their oxidized forms, and circular dichroism (CD) and electron paramagnetic resonance (EPR) of the reduced forms indicate that the overall structure is not affected by the mutations and reveal that there is no increase in solvent accessibility nor any reorientation of backbone amide dipoles or NH--S bonds. The structures, combined with detailed investigation of the variation of E0' with pH and temperature, show that the largest increases in E0' result from the introduction of positive charge due to protonation of the introduced His residues. The smaller (50--100 mV) increases observed for the neutral form are proposed to occur by directing a Hdelta+--Ndelta- dipole toward the reduced form of the cluster.

PubMed: 11875515

Experimental method

X-RAY DIFFRACTION (1.62 Å)