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Type: Artigo de periódico
Title: ZmPUMP encodes a fully functional monocot plant uncoupling mitochondrial protein whose affinity to fatty acid is increased with the introduction of a His pair at the second matrix loop
Author: Faavaro, RD
Borecky, J
Colombi, D
Maia, IG
Abstract: Uncoupling proteins (UCPs) are specialized mitochondrial transporter proteins that uncouple respiration from ATP synthesis. In this study, cDNA encoding maize uncoupling protein (ZmPUMP) was expressed in Eycherichia coli and recombinant ZmPUMP reconstituted in liposomes. ZmPUMP activity was associated with a linoleic acid (LA)-mediated H+ efflux with K-m of 56.36 +/- 0.27 mu M and V-max of 66.9 mu mol H+ min(-1) (mg prot)(-1). LA-mediated H+ fluxes were sensitive to ATP inhibition with K-i of 2.61 +/- 0.36 mM (at pH 7.2), a value similar to those for dicot UCPs. ZmPUMP was also used to investigate the importance of a histidine pair present in the second matrix loop of mammalian UCP1 and absent in plant UCPs. ZmPUMP with introduced His pair (Lys155His and Ala157His) displayed a 1.55-fold increase in LA-affinity while its activity remained unchanged. Our data indicate conserved properties of plant UCPs and suggest an enhancing but not essential role of the histidine pair in proton transport mechanism. (c) 2006 Elsevier Inc. All rights reserved.
Subject: uncoupling mitochondrial protein
UCP proton transport
functional reconstitution
mitochondrial carriers
plant mitochondria
Country: EUA
Editor: Academic Press Inc Elsevier Science
Rights: fechado
Identifier DOI: 10.1016/j.bbrx.2006.03.132
Date Issue: 2006
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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