The c13 Ring from a Thermoalkaliphilic ATP Synthase Reveals an Extended Diameter Due to a Special Structural Region
Research output: Contribution to journal › Research article › Contributed › peer-review
Contributors
Abstract
We have structurally characterized the c-ring from the thermoalkaliphilic Bacillus sp. strain TA2.A1 F1Fo-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 c11 rings. The inner ring of α-helices in c11 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 c13 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.
Details
Original language | English |
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Pages (from-to) | 611-618 |
Number of pages | 8 |
Journal | Journal of Molecular Biology |
Volume | 388 |
Issue number | 3 |
Publication status | Published - 8 May 2009 |
Peer-reviewed | Yes |
External IDs
PubMed | 19327366 |
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Keywords
ASJC Scopus subject areas
Keywords
- 2D crystallization, atomic force microscopy, electron microscopy, FF-ATP synthase c-ring, thermoalkaliphilic Bacillus sp. strain TA2.A1