Energy-driven subunit rotation at the interface between subunit a and the c oligomer in the FO sector of Escherichia coli ATP synthase

Subunit rotation within the F1 catalytic sector of the ATP synthase has been well documented, identifying the synthase as the smallest known rotary motor. In the membrane-embedded FO sector, it is thought that proton transport occurs at a rotor/stator interface between the oligomeric ring of c subunits (rotor) and the single-copy a subunit (stator). Here we report evidence for an energy-dependent rotation at this interface. FOF1 was expressed with a pair of substituted cysteines positioned to allow an intersubunit disulfide crosslink between subunit a and a c subunit [aN214C/cM65C; Jiang, W. & Fillingame, R. H. (1998) Proc. Natl. Acad. Sci. USA 95, 6607–6612]. Membranes were treated with N,N′-dicyclohexyl-[14C]carbodiimide to radiolabel the D61 residue on less than 20% of the c subunits. After oxidation to form an a–c crosslink, the c subunit properly aligned to crosslink to subunit a was found to contain very little 14C label relative to other members of the c ring. However, exposure to MgATP before oxidation significantly increased the radiolabel in the a–c crosslink, indicating that a different c subunit was now aligned with subunit a. This increase was not induced by exposure to MgADP/Pi. Furthermore, preincubation with MgADP and azide to inhibit F1 or with high concentrations of N,N′-dicyclohexylcarbodiimide to label most c subunits prevented the ATP effect. These results provide evidence for an energy-dependent rotation of the c ring relative to subunit a.

Mammalian Sug1 and c-Fos in the nuclear 26S proteasome.

In a search for regulatory proteins that interact with the leucine zipper motif of c-Fos in the yeast two-hybrid screen, we have identified a protein (FZA-B) that has extensive sequence similarity to SUG1 of Saccharomyces cerevisiae. Here we show that FZA-B can functionally substitute for SUG1 in yeast and that FZA-B interacts with Fos proteins in vitro through their leucine zippers. In rat liver and in HeLa cells, FZA-B is present in the 26S proteasome complex, as is c-Fos. Immobilized antibody raised against an FZA-B-specific peptide depleted peptidase activity, proteasomal proteins, FZA-B, and c-Fos from a 26S proteasome preparation. FZA-B is found predominantly in the nuclear fraction of COS cells expressing an FZA-B transgene and in the nuclear 26S proteasome of HeLa cells. We conclude that FZA-B is the mammalian homolog of SUG1 (mSug1) and that it is present in the nuclear 26S proteasome of cells. Our results suggest that mSug1 may be involved in the degradation of c-Fos and other transcription factors.

An Account of the Edinburgh Reform Jubilee, celebrated 10th August 1832 : also the Leith Reform Jubilee, celebrated same day. With an authentic description of the flags, banners, models, &c. carried in the processions /

Mode of access: Internet.

The works of Allan Ramsay; containing his poems, songs, proverbs, &c. chiefly in the Scottish dialect: also the original music of The gentle shepherd ...

Mode of access: Internet.

Copies of letters &c. read in the Legislative Council in the debate upon the Clergy Reserve Bill microform : January 17, 1840 /

Reproduction of original in: Library of the Public Archives of Canada.

Speech of Mr. Hayne, of South Carolina, on Mr. Foot's resolution, proposing an inquiry into the expediency of abolishing the office of surveyor general of public lands, and for discontinuing further surveys, &c. Delivered in the Senate of the United States January 21, 1830.

Mode of access: Internet.

Speech of Mr. Livingston, of Louisiana, on Mr. Foot's resolution, proposing an inquiry into the expediency of abolishing the office of Surveyor General of Public Lands, and for discontinuing further surveys, &c., delivered in the Senate of the United States, February 29, 1830.

Mode of access: Internet.

Safeguarding U.S. agriculture in the global environment.

"Issued September 2001"--Last p.

United States of America before the National Labor Relations Board, Case C-142 : in the matter of United States Steel Corporation (a New Jersey Corporation), Carnegie-Illinois Steel Corporation (a New Jersey Corporation) and Steel Workers Organizing Committee and Amalgamated Association of Iron, Steel and Tin Workers of North America.

"Exihibit B. Plans of employmee representation in effect at the plants of respondent, Carnegie-Illinois Steel Corporation"--Cover.

To what extent do currently accepted for-profit new project development success factors apply in the small nonprofit context in the UK?

DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY AND INFORMATION SERVICES WITH PRIOR ARRANGEMENT