Journal of Bioenergetics and Biomembranes

, Volume 42, Issue 6, pp 511–516

Transmembrane topology of subunit N of complex I (NADH:ubiquinone oxidoreductase) from Escherichia coli


DOI: 10.1007/s10863-010-9318-3

Cite this article as:
Amarneh, B. & Vik, S.B. J Bioenerg Biomembr (2010) 42: 511. doi:10.1007/s10863-010-9318-3


The transmembrane topology of subunit N from E. coli Complex I has been investigated. Chemical labeling of mono-substituted cysteine mutants was carried out in inverted membrane vesicles, and in whole cells, using 3-N-maleimidyl-propionyl biocytin (MPB). The results support a model of 14 transmembrane spans with both termini in the periplasm, and are consistent with the models of subunits L, M and N from the crystal structure of the membrane arm of the E. coli Complex I (Efremov et al. (2010) Nature 465, 441–445). In particular, the results do not support an unusual cytoplasmic localization of two likely transmembrane regions, as proposed in previous studies (Mathiesen and Hägerhäll (2002) Biochim Biophys Acta 1556, 121–132; Torres-Bacete, et al. (2009) J Biol Chem 284, 33062–33069).


Complex INADH:ubiquinone oxidoreductaseTransmembrane topologyCysteine mutagenesisChemical labeling3-N-maleimidyl-propionyl biocytin

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© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  1. 1.Department of Biological SciencesSouthern Methodist UniversityDallasUSA
  2. 2.Department of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasUSA