scholarly journals Evidence of the Proximity of ATP Synthase Subunits 6 (a) in the Inner Mitochondrial Membrane and in the Supramolecular Forms of Saccharomyces cerevisiae ATP Synthase

2011 ◽  
Vol 286 (41) ◽  
pp. 35477-35484 ◽  
Author(s):  
Jean Velours ◽  
Claire Stines-Chaumeil ◽  
Johan Habersetzer ◽  
Stéphane Chaignepain ◽  
Alain Dautant ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Atp Synthase ◽  
Mitochondrial Membrane ◽  
Transmembrane Helix ◽  
Disulfide Bridge ◽  
Cross Linking ◽  
Null Mutant ◽  
Terminal Part ◽  
Inner Mitochondrial Membrane ◽  
Membrane Spanning

The involvement of subunit 6 (a) in the interface between yeast ATP synthase monomers has been highlighted. Based on the formation of a disulfide bond and using the unique cysteine 23 as target, we show that two subunits 6 are close in the inner mitochondrial membrane and in the solubilized supramolecular forms of the yeast ATP synthase. In a null mutant devoid of supernumerary subunits e and g that are involved in the stabilization of ATP synthase dimers, ATP synthase monomers are close enough in the inner mitochondrial membrane to make a disulfide bridge between their subunits 6, and this proximity is maintained in detergent extract containing this enzyme. The cross-linking of cysteine 23 located in the N-terminal part of the first transmembrane helix of subunit 6 suggests that this membrane-spanning segment is in contact with its counterpart belonging to the ATP synthase monomer that faces it and participates in the monomer-monomer interface.

scholarly journals Expression of the Saccharomyces cerevisiae Gene YME1 in the Petite-Negative Yeast Schizosaccharomyces pombe Converts It to Petite-Positive

Genetics ◽  
2000 ◽  
Vol 154 (1) ◽  
pp. 147-154 ◽  
Author(s):  
Douglas J Kominsky ◽  
Peter E Thorsness
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitochondrial Dna ◽  
Schizosaccharomyces Pombe ◽  
Atp Synthase ◽  
Kluyveromyces Lactis ◽  
Blot Hybridization ◽  
Inner Mitochondrial Membrane ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mitochondrial Atp Synthase ◽  
Petite Negative Yeast

Abstract Organisms that can grow without mitochondrial DNA are referred to as “petite-positive” and those that are inviable in the absence of mitochondrial DNA are termed “petite-negative.” The petite-positive yeast Saccharomyces cerevisiae can be converted to a petite-negative yeast by inactivation of Yme1p, an ATP- and metal-dependent protease associated with the inner mitochondrial membrane. Suppression of this yme1 phenotype can occur by virtue of dominant mutations in the α- and γ-subunits of mitochondrial ATP synthase. These mutations are similar or identical to those occurring in the same subunits of the same enzyme that converts the petite-negative yeast Kluyveromyces lactis to petite-positive. Expression of YME1 in the petite-negative yeast Schizosaccharomyces pombe converts this yeast to petite-positive. No sequence closely related to YME1 was found by DNA-blot hybridization to S. pombe or K. lactis genomic DNA, and no antigenically related proteins were found in mitochondrial extracts of S. pombe probed with antisera directed against Yme1p. Mutations that block the formation of the F1 component of mitochondrial ATP synthase are also petite-negative. Thus, the F1 complex has an essential activity in cells lacking mitochondrial DNA and Yme1p can mediate that activity, even in heterologous systems.

scholarly journals Identification of sequences required for the import of human protoporphyrinogen oxidase to mitochondria

2004 ◽  
Vol 377 (2) ◽  
pp. 281-287 ◽  
Author(s):  
Rhian R. MORGAN ◽  
Rachel ERRINGTON ◽  
George H. ELDER
Keyword(s):  
Mitochondrial Membrane ◽  
Fluorescent Protein ◽  
Yellow Fluorescent Protein ◽  
Missense Mutations ◽  
Amino Acid Residues ◽  
Inner Mitochondrial Membrane ◽  
Inner Membrane ◽  
Protoporphyrinogen Oxidase ◽  
N Terminus ◽  
Membrane Spanning

Protoporphyrinogen oxidase (PPOX; EC 1.3.3.4), the penultimate enzyme of haem biosynthesis, is a nucleus-encoded flavoprotein strongly associated with the outer surface of the inner mitochondrial membrane. It is attached to this membrane by an unknown mechanism that appears not to involve a membrane-spanning domain. The pathway for its import to mitochondria and insertion into the inner membrane has not been established. We have fused human PPOXs containing N-terminal deletions, C-terminal deletions or missense mutations to yellow fluorescent protein (YFP) and have used these constructs to investigate the mitochondrial import of PPOX in human cells. We show that all the information required for efficient import is contained within the first 250 amino acid residues of human PPOX and that targeting to mitochondria is prevented by fusion of YFP to the N-terminus. Deletion of between 151 and 175 residues from the N-terminus is required to abolish import, whereas shorter deletions impair its efficiency. Fully efficient targeting appears to require both a major targeting signal, the whole or part of which is contained between residues 151 and 175, and which may be involved in anchoring to the inner mitochondrial membrane, together with interaction between this region and a sequence(s) within the first 150 residues. These features suggest that the mechanism for import of human PPOX to mitochondria differs from those identified for the translocation of nucleus-encoded, membrane-spanning, inner membrane proteins. In addition, a missense mutation outside this region (Val335→Gly) prevented targeting to mitochondria and delayed the appearance of YFP fluorescence. This mutation appeared to prevent import by a direct effect on protein folding rather than by altering a sequence required for targeting. It may lead to sequestration of the PPOX–YFP construct in an unfolded conformation, followed by proteolytic degradation, possibly through enhanced binding to a cytosolic chaperone protein.

scholarly journals Transmembrane signaling in the sensor kinase DcuS ofEscherichia coli: A long-range piston-type displacement of transmembrane helix 2

2015 ◽  
Vol 112 (35) ◽  
pp. 11042-11047 ◽  
Author(s):  
Christian Monzel ◽  
Gottfried Unden
Keyword(s):  
Amino Acid ◽  
Ligand Binding ◽  
Transmembrane Helix ◽  
Binding Domain ◽  
Cross Linking ◽  
Sensor Kinase ◽  
Amino Acid Residues ◽  
Terminal Part ◽  
Type Shift

The C4-dicarboxylate sensor kinase DcuS is membrane integral because of the transmembrane (TM) helices TM1 and TM2. Fumarate-induced movement of the helices was probed in vivo by Cys accessibility scanning at the membrane–water interfaces after activation of DcuS by fumarate at the periplasmic binding site. TM1 was inserted with amino acid residues 21–41 in the membrane in both the fumarate-activated (ON) and inactive (OFF) states. In contrast, TM2 was inserted with residues 181–201 in the OFF state and residues 185–205 in the ON state. Replacement of Trp 185 by an Arg residue caused displacement of TM2 toward the outside of the membrane and a concomitant induction of the ON state. Results from Cys cross-linking of TM2/TM2′ in the DcuS homodimer excluded rotation; thus, data from accessibility changes of TM2 upon activation, either by ligand binding or by mutation of TM2, and cross-linking of TM2 and the connected region in the periplasm suggest a piston-type shift of TM2 by four residues to the periplasm upon activation (or fumarate binding). This mode of function is supported by the suggestion from energetic calculations of two preferred positions for TM2 insertion in the membrane. The shift of TM2 by four residues (or 4–6 Å) toward the periplasm upon activation is complementary to the periplasmic displacement of 3–4 Å of the C-terminal part of the periplasmic ligand-binding domain upon ligand occupancy in the citrate-binding domain in the homologous CitA sensor kinase.

scholarly journals Dimer ribbons of ATP synthase shape the inner mitochondrial membrane

2008 ◽  
Vol 27 (7) ◽  
pp. 1154-1160 ◽  
Author(s):  
Mike Strauss ◽  
Götz Hofhaus ◽  
Rasmus R Schröder ◽  
Werner Kühlbrandt
Keyword(s):  
Atp Synthase ◽  
Mitochondrial Membrane ◽  
Inner Mitochondrial Membrane

Relationship of Subunit 8 of Yeast ATP Synthase and the Inner Mitochondrial Membrane

2008 ◽  
Vol 227 (3) ◽  
pp. 745-752
Author(s):  
Theo Papakonstantinou ◽  
Ruby H. P. Law ◽  
Stephen Manon ◽  
Rodney J. Devenish ◽  
Phillip Nagley
Keyword(s):  
Atp Synthase ◽  
Mitochondrial Membrane ◽  
Inner Mitochondrial Membrane ◽  
Relationship Of
Sign in / Sign up

Export Citation Format

Share Document