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Global topology analysis of the Escherichia coli inner membrane proteome
Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
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2005 In: Science, Vol. 308, no 5726, 1321-1323 p.Article in journal (Refereed) Published
Place, publisher, year, edition, pages
2005. Vol. 308, no 5726, 1321-1323 p.
URN: urn:nbn:se:su:diva-23011OAI: diva2:189898
Part of urn:nbn:se:su:diva-1330Available from: 2006-10-29 Created: 2006-10-29Bibliographically approved
In thesis
1. The Ins and Outs of Membrane Proteins: Topology Studies of Bacterial Membrane Proteins
Open this publication in new window or tab >>The Ins and Outs of Membrane Proteins: Topology Studies of Bacterial Membrane Proteins
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

α-helical membrane proteins comprise about a quarter of all proteins in a cell and carry out a wide variety of essential cellular functions. This thesis is focused on topology analyses of bacterial membrane proteins. The topology describes the two-dimensional structural arrangement of a protein relative to the membrane.

By combining large-scale experimental and bioinformatics techniques we have produced experimentally constrained topology models for the major part of the Escherichia coli membrane proteome. This represents a substantial increase in available topology information for bacterial membrane proteins.

Many membrane protein structures show signs of internal duplication and approximate two-fold in-plane symmetry. We propose a step-wise pathway to explain how proteins with such internal inverted repeats have evolved. The pathway is based on the ‘positive-inside’ rule and starts with a protein that can adopt two topologies in the membrane, i.e. a “dual” topology protein. The gene encoding the dual topology protein is duplicated and eventually, through re-distribution of positively charge residues, the two resulting homologous proteins become fixed in opposite orientations in the membrane. Finally, the two proteins may fuse into one single polypeptide with an internal inverted repeat structure.

Finally, we re-create the proposed step-wise evolutionary pathway in the laboratory by showing that only a small number of mutations are required in order to transform the homo-dimeric, dual topology protein EmrE into a hetero-dimeric complex composed of two oppositely oriented proteins.

Place, publisher, year, edition, pages
Stockholm: Institutionen för biokemi och biofysik, 2006. 58 p.
membrane protein, topology, dual topology
National Category
urn:nbn:se:su:diva-1330 (URN)91-7155-311-8 (ISBN)
Public defence
2006-12-01, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 12 A, Stockholm, 10:00
Available from: 2006-10-29 Created: 2006-10-29 Last updated: 2010-08-25Bibliographically approved

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