Physiological relevance, localization and substrate specificity of the alternative (type II) mitochondrial NADH dehydrogenases of Ogataea parapolymorpha

Juergens, H., Mielgo-Gómez, Á., Godoy-Hernández, A., ter Horst, J., Nijenhuis, J. M., McMillan, D. G.G. ORCID: https://orcid.org/0000-0001-6614-4494 and Mans, R. (2024) Physiological relevance, localization and substrate specificity of the alternative (type II) mitochondrial NADH dehydrogenases of Ogataea parapolymorpha. Frontiers in Microbiology, 15. 1473869. ISSN 1664-302X doi: 10.3389/fmicb.2024.1473869

Abstract/Summary

Mitochondria from Ogataea parapolymorpha harbor a branched electron-transport chain containing a proton-pumping Complex I NADH dehydrogenase and three Type II NADH dehydrogenases (NDH-2). To investigate the physiological role, localization and substrate specificity of these enzymes, the growth of various NADH dehydrogenase knockout mutants was quantitatively characterized in shake-flask and chemostat cultures, followed by oxygen-uptake experiments with isolated mitochondria. NAD(P)H:quinone oxidoreduction of the three NDH-2 were individually assessed. Our findings reveal that the O. parapolymorpha respiratory chain contains an internal NADH-accepting NDH-2 (Ndh2-1/OpNdi1), at least one external NAD(P)H-accepting enzyme, and likely additional mechanisms for respiration-linked oxidation of cytosolic NADH. Metabolic regulation appears to prevent competition between OpNdi1 and Complex I for mitochondrial NADH. With the exception of OpNdi1, the respiratory chain of O. parapolymorpha exhibits metabolic redundancy and tolerates deletion of multiple NADH-dehydrogenase genes without compromising fully respiratory metabolism.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/123228
Identification Number/DOI	10.3389/fmicb.2024.1473869
Refereed	Yes
Divisions	Life Sciences > School of Biological Sciences > Biomedical Sciences
Publisher	Frontiers
Download/View statistics	View download statistics for this item