Structural highlights
Publication Abstract from PubMed2-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-A and 2.80-A 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 Glu45alpha 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). A reverse TCA cycle 2-oxoacid:ferredoxin oxidoreductase that makes C-C bonds from CO2.,Chen PY, Li B, Drennan CL, Elliott SJ Joule. 2019 Feb 20;3(2):595-611. doi: 10.1016/j.joule.2018.12.006. Epub 2019 Jan , 4. PMID:31080943[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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