6OHK

Crystal structure of Fusobacterium nucleatum flavodoxin mutant K13G bound to flavin mononucleotide

Summary for 6OHK

• Entry DOI: 10.2210/pdb6ohk/pdb
• Descriptor: Flavodoxin, FLAVIN MONONUCLEOTIDE, GLYCEROL, ... (4 entities in total)
• Functional Keywords: flavodoxin, reduction potential, flavin mononucleotide, electron transfer, electron transport
• Biological source: Fusobacterium nucleatum
• Total number of polymer chains: 1
• Total formula weight: 19609.15

Authors

Kolesnikov, M.,Murphy, M.E.P. (deposition date: 2019-04-05, release date: 2019-06-05, Last modification date: 2024-03-13)

Primary citation

Mothersole, R.G.,Macdonald, M.,Kolesnikov, M.,Murphy, M.E.P.,Wolthers, K.R.
Structural insight into the high reduction potentials observed for Fusobacterium nucleatum flavodoxin.
Protein Sci., 28:1460-1472, 2019

PubMed Abstract: Flavodoxins are small flavin mononucleotide (FMN)-containing proteins that mediate a variety of electron transfer processes. The primary sequence of flavodoxin from Fusobacterium nucleatum, a pathogenic oral bacterium, is marked with a number of distinct features including a glycine to lysine (K13) substitution in the highly conserved phosphate-binding loop (T/S-X-T-G-X-T), variation in the aromatic residues that sandwich the FMN cofactor, and a more even distribution of acidic and basic residues. The E (oxidized/semiquinone; -43 mV) and E (semiquinone/hydroquinone; -256 mV) are the highest recorded reduction potentials of known long-chain flavodoxins. These more electropositive values are a consequence of the apoprotein binding to the FMN hydroquinone anion with ~70-fold greater affinity compared to the oxidized form of the cofactor. Inspection of the FnFld crystal structure revealed the absence of a hydrogen bond between the protein and the oxidized FMN N5 atom, which likely accounts for the more electropositive E . The more electropositive E is likely attributed to only one negatively charged group positioned within 12 Å of the FMN N1. We show that natural substitutions of highly conserved residues partially account for these more electropositive reduction potentials.

PubMed: 31116469
DOI: 10.1002/pro.3661

Experimental method

X-RAY DIFFRACTION (1.2 Å)