A novel functional element in the N-terminal region of Arum concinnatum alternative oxidase is indispensable for catalytic activity of the enzyme in HeLa cells

Simple item page
dc.contributor.authorKakizaki, Y.
dc.contributor.authorSeymour, R.
dc.contributor.authorIto, K.
dc.date.issued2010
dc.description.abstractAlternative oxidase (AOX) is a quinol-oxygen oxidoreductase, which is known to possess a dicarboxylate diiron reaction center held in structurally postulated alpha-helical bundle. However, little is known about the structural or functional features of its N-terminal region in any organism, with the exception of a regulatory cysteine residue (CysI) in angiosperm plants. Here, we show that transcripts of two AOX1 isozymes (AcoAOX1a and AcoAOX1b) are coexpressed in thermogenic appendices of Arum concinnatum, while their enzymatic activities seem to be distinct. Namely, AcoAOX1a, an abundantly expressed transcript in vivo, shows an apparent cyanide-insensitive and n-propyl gallate-sensitive respiration during ectopic expression of the protein in HeLa cells, whereas AcoAOX1b exhibits a lower transcript expression, and appears to be totally inactive as AOX at the protein level. Our functional analyses further reveal that an E83K substitution in AcoAOX1b, which is located far upstream of CysI in the N-terminal region, is the cause of this loss of function. These results suggest the presence of a naturally occurring inactive AOX homologue in thermogenic plants. Accordingly, our results further imply that the N-terminal region of the AOX protein functionally contributes to the dynamic activities of respiratory control within the mitochondria.
dc.description.statementofresponsibilityYusuke Kakizaki, Roger S. Seymour, Kikukatsu Ito
dc.identifier.citationBiochimica et Biophysica Acta - Bioenergetics, 2010; 1797(1):20-28
dc.identifier.doi10.1016/j.bbabio.2009.07.006
dc.identifier.issn0005-2728
dc.identifier.issn1879-2650
dc.identifier.orcidSeymour, R. [0000-0002-3395-0059]
dc.identifier.urihttp://hdl.handle.net/2440/61858
dc.language.isoen
dc.publisherElsevier Science BV
dc.relation.granthttp://purl.org/au-research/grants/arc/DP0771854
dc.rightsCopyright © 2009 Elsevier B.V. All rights reserved.
dc.source.urihttps://doi.org/10.1016/j.bbabio.2009.07.006
dc.subjectAlternative oxidase
dc.subjectArum lily
dc.subjectThermogenesis
dc.subjectInactive isoform
dc.subjectN-terminus
dc.subjectLoss of function
dc.titleA novel functional element in the N-terminal region of Arum concinnatum alternative oxidase is indispensable for catalytic activity of the enzyme in HeLa cells
dc.typeJournal article
pubs.publication-statusPublished

Files

Collections

Earth and Environmental Sciences publications