Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Lateral proton transfer between the membrane and a membrane protein.
Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. (Peter Brzezinski)
2009 (English)In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 48, no 10, 2173-9 p.Article in journal (Refereed) Published
Abstract [en]

Proton transport across biological membranes is a key step of the energy conservation machinery in living organisms, and it has been proposed that the membrane itself plays an important role in this process. In the present study we have investigated the effect of incorporation of a proton transporter, cytochrome c oxidase, into a membrane on the protonation kinetics of a fluorescent pH-sensitive probe attached at the surface of the protein. The results show that proton transfer to the probe was slightly accelerated upon attachment at the protein surface (approximately 7 x 1010 s(-1) M(-1), compared to the expected value of (1-2) x 10(10) s(-1) M(-1)), which is presumably due to the presence of acidic/His groups in the vicinity. Upon incorporation of the protein into small unilamellar phospholipid vesicles the rate increased by more than a factor of 400 to approximately 3 x 10(13) s(-1) M(-1), which indicates that the protein-attached probe is in rapid protonic contact with the membrane surface. The results indicate that the membrane acts to accelerate proton uptake by the membrane-bound proton transporter.

Place, publisher, year, edition, pages
2009. Vol. 48, no 10, 2173-9 p.
National Category
Biochemistry and Molecular Biology
Identifiers
URN: urn:nbn:se:su:diva-36116DOI: 10.1021/bi8022152ISI: 000264059500012PubMedID: 19166299OAI: oai:DiVA.org:su-36116DiVA: diva2:288793
Available from: 2010-01-21 Created: 2010-01-21 Last updated: 2017-12-12Bibliographically approved
In thesis
1. Membrane effects on proton transfer in cytochrome c oxidase
Open this publication in new window or tab >>Membrane effects on proton transfer in cytochrome c oxidase
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The biological membrane is composed of lipids and proteins that make up dynamic barriers around cells and organelles. Membrane-spanning proteins are involved in many key processes in the cell such as energy conversion, nerve conduction and signal transduction. These proteins interact closely with lipids as well as with other proteins in the membrane, which modulates and affects their structure and function. In the energy-conversion process, membrane-bound proton-transport proteins maintain an electrochemical proton gradient across the mitochondrial inner membrane or the cytoplasmic membrane of bacteria. This gradient is utilized for ATP synthesis or transport of ions and molecules across the membrane. Results from earlier studies have shown that proton transporters are influenced by their environment.

Here, one of these proton transporters, cytochrome c oxidase, has been purified and reconstituted into liposomes or nanodiscs and membrane effects on specific proton-transfer processes were studied. In these studies we observed that the membrane accelerated proton transfer to the surface of cytochrome c oxidase and that there is a protonic link, via a Glu residue that mediates proton transfer from the membrane surface to a proton-transfer pathway in this protein. In addition, the membrane was shown to modulate specific internal electron and proton-transfer reactions.

The results from these studies show that the membrane composition influences transmembrane transport. Consequently, our understanding of these processes requires investigation of these transporter proteins in different membrane-mimetic systems of variable and well-defined composition. Furthermore, the data show that membrane surfaces facilitate lateral proton transfer which is presumably essential for maintaining high efficiency in energy conversion. This is particular important in organisms such as alkaliphilic bacteria where the driving force of the electrochemical proton gradient, between the bulk solution on each side of the membrane is not sufficient for ATP synthesis.

Place, publisher, year, edition, pages
Department of Biochemistry and Biophysics, Stockholm University, 2012. 57 p.
Keyword
cytochrom c oxidase, lipids, membrane, proton transfer
National Category
Biochemistry and Molecular Biology
Research subject
Biochemistry
Identifiers
urn:nbn:se:su:diva-75633 (URN)978-91-7447-482-4 (ISBN)
Public defence
2012-06-15, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (English)
Opponent
Supervisors
Available from: 2012-05-11 Created: 2012-04-24 Last updated: 2012-05-15Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Öjemyr, LindaBrzezinski, Peter
By organisation
Department of Biochemistry and Biophysics
In the same journal
Biochemistry
Biochemistry and Molecular Biology

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 50 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf