Database of articles cited by EMDB/PDB/SASBDB data

Keywords
Structure methods	All X-ray diffraction NMR electron microscopy small angle scattering neutron diffraction fiber diffraction powder diffraction infrared spectroscopy EPR fluorescence transfer theoretical model Hybrid
Author
Journal
IF	>30 >20 >10 >5 all

Title	Cryo-EM reveals a composite flavobicluster electron bifurcation site in the Bfu family member NfnABC.
Journal, issue, pages	Commun Biol, Vol. 8, Issue 1, Page 239, Year 2025
Publish date	Feb 14, 2025
Authors	Hua Li / Gerrit J Schut / Xiang Feng / Michael W W Adams / Huilin Li /
PubMed Abstract	The BfuABC family is a diverse group of electron bifurcating enzymes that play key roles in anaerobic microbial metabolism. Previous studies have focused almost exclusively on the BfuABC-type ...The BfuABC family is a diverse group of electron bifurcating enzymes that play key roles in anaerobic microbial metabolism. Previous studies have focused almost exclusively on the BfuABC-type hydrogenases but the mechanism and site of electron bifurcation remain unknown. Herein we focus on the Caldicellulosiruptor saccharolyticus (Csac) NfnABC-type Bfu enzyme that catalyzes the oxidation of NADPH and simultaneous reduction of NAD and the redox protein ferredoxin (Fd). Cryo-EM structures determined with and without NAD and Fd reveal seven FeS clusters and one FAD in NfnA, one FeS cluster in NfnC, and three FeS clusters, two Zn ions, and one FMN in NfnB. The Zn ions take the place of FeS clusters previously proposed in other Bfu family members. Csac Nfn for the first time defines the minimum bifurcation site as a flavobicluster consisting of FMN, a [4Fe-4S] (B1) cluster and a [2Fe-2S] (C1) cluster. Binding of NAD to the FMN triggers a series of conformational changes, crucial to the bifurcation of two electron pairs derived from NADPH by the [B1-FMN-C1] flavobicluster into low and high potential electrons that reduce Fd and NAD, respectively. The structures lay the foundation for investigations of the proposed reaction cycle common to all Bfu enzymes.
External links	Commun Biol / PubMed:39953182 / PubMed Central
Methods	EM (single particle)
Resolution	2.7 - 3.3 Å
Structure data	EMDB-44749: The consensus EM map of electron bifurcating Nfn-ABC holoenzyme from Caldicellulosiruptor saccharolyticus Method: EM (single particle) / Resolution: 2.7 Å EMDB-44750: The focused refined map of the NfnBC subunits of electron bifurcating Nfn-ABC holoenzyme from Caldicellulosiruptor saccharolyticus Method: EM (single particle) / Resolution: 3.2 Å 44751 9bov EMDB-44751, PDB-9bov: Structure of electron bifurcating Nfn-ABC complexed with NAD from Caldicellulosiruptor saccharolyticus Method: EM (single particle) / Resolution: 3.0 Å EMDB-44752: The consensus EM map of electron bifurcating Nfn-ABC complexed with NAD from Caldicellulosiruptor saccharolyticus Method: EM (single particle) / Resolution: 3.0 Å EMDB-44753: The focused refined map of NfnBC subunits of Csac Nfn-ABC complexed with NAD from Caldicellulosiruptor saccharolyticus Method: EM (single particle) / Resolution: 3.3 Å 44761 9bp5 EMDB-44761, PDB-9bp5: Structure of electron bifurcating Nfn-ABC holoenzyme from Caldicellulosiruptor saccharolyticus Method: EM (single particle) / Resolution: 2.7 Å
Chemicals	ChemComp-FES: FE2/S2 (INORGANIC) CLUSTER ChemComp-SF4: IRON/SULFUR CLUSTER ChemComp-FAD: FLAVIN-ADENINE DINUCLEOTIDE / FADYM ChemComp-FMN: FLAVIN MONONUCLEOTIDE ChemComp-ZN: Unknown entry ChemComp-NAD: NICOTINAMIDE-ADENINE-DINUCLEOTIDE / NADYM
Source	caldicellulosiruptor saccharolyticus (bacteria)
Keywords	OXIDOREDUCTASE / Electron bifurcating enzyme / Nfn-type BfuABC complex / FMN/B1/C1 bifurcation site