6N2N image
Entry Detail
PDB ID:
6N2N
Keywords:
Title:
Crystal structure of 2-oxoglutarate:ferredoxin oxidoreductase from Magnetococcus marinus
Biological Source:
PDB Version:
Deposition Date:
2018-11-13
Release Date:
2019-03-20
Method Details:
Experimental Method:
Resolution:
1.94 Å
R-Value Free:
0.20
R-Value Work:
0.16
R-Value Observed:
0.16
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Pyruvate flavodoxin/ferredoxin oxidoreductase domain protein
Chain IDs:A, C
Chain Length:573
Number of Molecules:2
Biological Source:Magnetococcus marinus (strain ATCC BAA-1437 / JCM 17883 / MC-1)
Polymer Type:polypeptide(L)
Description:Pyruvate ferredoxin/flavodoxin oxidoreductase, beta subunit
Chain IDs:B, D
Chain Length:292
Number of Molecules:2
Biological Source:Magnetococcus marinus (strain ATCC BAA-1437 / JCM 17883 / MC-1)
Primary Citation
A reverse TCA cycle 2-oxoacid:ferredoxin oxidoreductase that makes C-C bonds from CO2.
Joule 3 595 611 (2019)
PMID: 31080943 DOI: 10.1016/j.joule.2018.12.006

Abstact

2-oxoglutarate:ferredoxin oxidoreductase (OGOR) is a thiamine pyrophosphate (TPP) and [4Fe-4S] cluster-dependent enzyme from the reductive tricarboxylic acid (rTCA) cycle that fixes CO2 to succinyl-CoA, forming 2-oxoglutarate and CoA. Here we report an OGOR from the rTCA cycle of Magnetococcus marinus MC-1, along with all three potential ferredoxin (Fd) redox partners. We demonstrate MmOGOR operates bidirectionally (both CO2-fixing and 2-oxoglutarate oxidizing), and that only one Fd (MmFd1) supports efficient catalysis. Our 1.94-Å and 2.80-Å resolution crystal structures of native and substrate-bound forms of MmOGOR reveal the determinants of substrate specificity and CoA-binding in an OGOR, and illuminate the [4Fe-4S] cluster environment, portraying the electronic conduit allowing MmFd1 to be wired to the bound-TPP. Structural and biochemical data further identify Glu45α as a mobile residue that impacts catalytic bias toward CO2-fixation although it makes no direct contact with TPP-bound intermediates, indicating that reaction directionality can be tuned by second layer interactions. (149 of 150 words limit).

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