Characterization of the N-Terminal Targeting Signal Binding Domain of the Mitochondrial Outer Membrane Receptor, Tom20†

Biochemistry ◽  
1998 ◽  
Vol 37 (38) ◽  
pp. 13052-13058 ◽  
Author(s):  
Enrico Schleiff ◽  
Joanne L. Turnbull
Keyword(s):  
Outer Membrane ◽  
Binding Domain ◽  
Membrane Receptor ◽  
Mitochondrial Outer Membrane ◽  
Outer Membrane Receptor ◽  
Targeting Signal

scholarly journals Characterization of a Gene Encoding the Outer Membrane Receptor for Ferric Enterobactin in Aeromonas hydrophila ATCC 7966T

2013 ◽  
Vol 77 (2) ◽  
pp. 353-360 ◽  
Author(s):  
Tatsuya FUNAHASHI ◽  
Tomotaka TANABE ◽  
Katsushiro MIYAMOTO ◽  
Hiroshi TSUJIBO ◽  
Jun MAKI ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Aeromonas Hydrophila ◽  
Membrane Receptor ◽  
Outer Membrane Receptor ◽  
Gene Encoding

scholarly journals Identification and characterization of an iron-regulated gene, chtA, required for the utilization of the xenosiderophores aerobactin, rhizobactin 1021 and schizokinen by Pseudomonas aeruginosa

Microbiology ◽  
2006 ◽  
Vol 152 (4) ◽  
pp. 945-954 ◽  
Author(s):  
Páraic Ó Cuív ◽  
Paul Clarke ◽  
Michael O'Connell
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Membrane Receptor ◽  
Outer Membrane Receptor ◽  
Significant Similarity ◽  
Hydroxamate Siderophores ◽  
Insertional Inactivation ◽  
Titration Assay

Pseudomonas aeruginosa utilizes several xenosiderophores under conditions of iron limitation, including the citrate hydroxamate siderophore aerobactin. Analysis of the P. aeruginosa genome sequence revealed the presence of two genes, chtA (PA4675) and PA1365, encoding proteins displaying significant similarity to the aerobactin outer-membrane receptor, IutA, of Escherichia coli. The chtA and PA1365 genes were mutated by insertional inactivation and it was demonstrated that ChtA is the outer-membrane receptor for aerobactin. ChtA also mediated the utilization of rhizobactin 1021 and schizokinen, which are structurally similar to aerobactin. In contrast to the utilization of other xenosiderophores by P. aeruginosa, there was no apparent redundancy in the utilization of aerobactin, rhizobactin 1021 and schizokinen. The utilization of citrate hydroxamate siderophores by P. aeruginosa was demonstrated to be TonB1 dependent. A Fur box was identified in the region directly upstream of chtA and it was demonstrated by the in vivo Fur titration assay that this region is capable of binding Fur and accordingly that expression of chtA is iron regulated. The PA1365 mutant was unaffected in the utilization of citrate hydroxamate siderophores.

scholarly journals Characterization of the signal that directs Bcl-xL, but not Bcl-2, to the mitochondrial outer membrane

2003 ◽  
Vol 160 (1) ◽  
pp. 53-64 ◽  
Author(s):  
Thomas Kaufmann ◽  
Sarah Schlipf ◽  
Javier Sanz ◽  
Karin Neubert ◽  
Reuven Stein ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Mitochondrial Outer Membrane ◽  
Mitochondrial Targeting ◽  
Mitochondrial Localization ◽  
Intracellular Membranes ◽  
Bona Fide ◽  
Targeting Signal ◽  
Tm Domain ◽  
Mitochondrial Targeting Sequences

It is assumed that the survival factors Bcl-2 and Bcl-xL are mainly functional on mitochondria and therefore must contain mitochondrial targeting sequences. Here we show, however, that only Bcl-xL is specifically targeted to the mitochondrial outer membrane (MOM) whereas Bcl-2 distributes on several intracellular membranes. Mitochondrial targeting of Bcl-xL requires the COOH-terminal transmembrane (TM) domain flanked at both ends by at least two basic amino acids. This sequence is a bona fide targeting signal for the MOM as it confers specific mitochondrial localization to soluble EGFP. The signal is present in numerous proteins known to be directed to the MOM. Bcl-2 lacks the signal and therefore localizes to several intracellular membranes. The COOH-terminal region of Bcl-2 can be converted into a targeting signal for the MOM by increasing the basicity surrounding its TM. These data define a new targeting sequence for the MOM and propose that Bcl-2 acts on several intracellular membranes whereas Bcl-xL specifically functions on the MOM.

Characterization of the stability functions and inverted repeat structure X3 of the IncFI plasmid ColV2-K94

1986 ◽  
Vol 32 (10) ◽  
pp. 806-813
Author(s):  
Peter C. Weber ◽  
Sunil Palchaudhuri
Keyword(s):  
Outer Membrane ◽  
Inverted Repeat ◽  
Iron Uptake ◽  
Membrane Receptor ◽  
Outer Membrane Receptor ◽  
Plasmid Maintenance ◽  
Stability Functions ◽  
Repeat Structure ◽  
The Stability

A region of the IncFI plasmid ColV2-K94 which showed homology to the sop partitioning genes of F was cloned and characterized in an attempt to study the stability functions of this element. The sop region contained the incD incompatibility determinant common to many IncFI plasmids, but could not confer on ColV2-K94 miniplasmids the same stable inheritance found in the intact ColV2-K94; thus, other functions appear to be required for efficient plasmid maintenance. Adjacent to the area of sop homology was the X3 region, which was found to contain three inverted IS1-like sequences. The X3 region of ColV2-K94 was similar in organization to the aerobactin iron uptake region of ColV3-K30, but ColV2-K94 lacked the ability to synthesize either the aerobactin siderophore or its outer membrane receptor.

Characterization of rat TOM70 as a receptor of the preprotein translocase of the mitochondrial outer membrane

2002 ◽  
Vol 115 (9) ◽  
pp. 1895-1905 ◽  
Author(s):  
Hiroyuki Suzuki ◽  
Maki Maeda ◽  
Katsuyoshi Mihara
Keyword(s):  
Outer Membrane ◽  
Transmembrane Domain ◽  
Structural Similarity ◽  
Mitochondrial Outer Membrane ◽  
Outer Membranes ◽  
Sequence Identity ◽  
Arginine Residues ◽  
Targeting Signal ◽  
Mitochondria Targeting

We cloned a ∼70 kDa rat mitochondrial outer membrane protein (OM70)with a sequence identity of 28.1% and 20.1% with N. crassa and S. cerevisiae Tom70, respectively. Even with this low sequence identity,however, the proteins share a remarkable structural similarity: they have 7-10 tetratricopeptide repeat motifs and are anchored to the outer membrane through the N-terminal transmembrane domain with the bulk portion located in the cytosol. Antibodies against OM70 inhibited import of preproteins, such as the ADP/ATP carrier and rTOM40, that use internal targeting signals but not the import of cleavable presequence-containing preproteins. Blue native gel electrophoresis and immunoprecipitation of digitoninsolubilized mitochondrial outer membranes revealed that OM70 was loosely associated with the ∼400 kDa translocase complex of the mitochondrial outer membrane, which contains rTOM22 and rTOM40. A yeast two-hybrid system demonstrated that OM70 interacted with rTOM20 and rTOM22 through the cytoplasmic domains. Thus, OM70 is a functional homologue of fungal Tom70 and functions as a receptor of the preprotein import machinery of the rat mitochondrial outer membrane. Furthermore, the N-terminal 66 residue region of OM70, which comprises a hydrophilic 41 residue N-terminal domain, a 22 residue transmembrane domain and three arginine residues, is sufficient to act as a mitochondria-targeting signal, and the arginine cluster is crucial for this function.

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