The c13 ring from a thermoalkaliphilic ATP synthase reveals an extended diameter due to a special structural region.

TitleThe c13 ring from a thermoalkaliphilic ATP synthase reveals an extended diameter due to a special structural region.
Publication TypeJournal Article
Year of Publication2009
AuthorsMatthies, D, Preiss, L, Klyszejko, AL, Müller, DJ, Cook, GM, Vonck, J, Meier, T
JournalJ Mol Biol
Volume388
Issue3
Pagination611-8
Date Published2009 May 08
ISSN1089-8638
KeywordsAmino Acid Sequence, Bacillus, Bacterial Proteins, Cryoelectron Microscopy, Crystallization, Microscopy, Atomic Force, Mitochondrial Proton-Translocating ATPases, Models, Molecular, Molecular Sequence Data, Protein Structure, Quaternary, Protein Structure, Tertiary, Sequence Alignment
Abstract

We have structurally characterized the c-ring from the thermoalkaliphilic Bacillus sp. strain TA2.A1 F(1)F(o)-ATP synthase. Atomic force microscopy imaging and cryo-electron microscopy analyses confirm previous mass spectrometric data indicating that this c-ring contains 13 c-subunits. The cryo-electron microscopy map obtained from two-dimensional crystals shows less closely packed helices in the inner ring compared to those of Na(+)-binding c(11) rings. The inner ring of alpha-helices in c(11) rings harbors a conserved GxGxGxGxG motif, with glycines located at the interface between c-subunits, which is responsible for the close packing of these helices. This glycine motif is altered in the c(13) ring of Bacillus sp. strain TA2.A1 to AxGxSxGxS, leading to a change in c-c subunit contacts and thereby enlarging the c-ring diameter to host a greater number of c-subunits. An altered glycine motif is a typical feature of c-subunit sequences in alkaliphilic Bacillus species. We propose that enlarged c-rings in proton-dependent F-ATP synthases may represent an adaptation to facilitate ATP synthesis at low overall proton-motive force, as occurs in bacteria that grow at alkaline pH.

DOI10.1016/j.jmb.2009.03.052
Alternate JournalJ. Mol. Biol.
Citation Key10.1016/j.jmb.2009.03.052
PubMed ID19327366