Insights Into Mitochondrial Fatty Acid Synthesis from the Structure of Heterotetrameric 3-Ketoacyl-Acp Reductase/3R-Hydroxyacyl-Coa Dehydrogenase.Venkatesan, R., Sah-Teli, S.K., Awoniyi, L.O., Jiang, G., Prus, P., Kastaniotis, A.J., Hiltunen, J.K., Wierenga, R.K., Chen, Z.
(2014) Nat Commun 5: 4805
- PubMed: 25203508
- DOI: https://doi.org/10.1038/ncomms5805
- Primary Citation of Related Structures:
- PubMed Abstract:
Mitochondrial fatty acid synthesis (mtFAS) is essential for respiratory growth in yeast and mammalian embryonic survival. The human 3-ketoacyl-acyl carrier protein (ACP) reductase (KAR) of mtFAS is a heterotetrameric α2β2-assembly composed of 17β-hydroxysteroid dehydrogenase type-8 (HSD17B8, α-subunit) and carbonyl reductase type-4 (CBR4, β-subunit). Here we provide a structural explanation for the stability of the heterotetramer from the crystal structure with NAD(+) and NADP(+) bound to the HSD17B8 and CBR4 subunits, respectively, and show that the catalytic activity of the NADPH- and ACP-dependent CBR4 subunit is crucial for a functional HsKAR. Therefore, mtFAS is NADPH- and ACP dependent, employing the 3R-hydroxyacyl-ACP intermediate. HSD17B8 assists in the formation of the competent HsKAR assembly. The intrinsic NAD(+)- and CoA-dependent activity of the HSD17B8 subunit on the 3R-hydroxyacyl-CoA intermediates may indicate a role for this subunit in routing 3R-hydroxyacyl-CoA esters, potentially arising from the metabolism of unsaturated fatty acids, into the mitochondrial β-oxidation pathway.
Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu, University of Oulu, PO Box 5400, Oulu FI-90014, Finland.