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rdf:type |
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lifeskim:mentions |
umls-concept:C0010749,
umls-concept:C0033809,
umls-concept:C0205245,
umls-concept:C0243111,
umls-concept:C0449432,
umls-concept:C0521009,
umls-concept:C0678594,
umls-concept:C1179435,
umls-concept:C1254042,
umls-concept:C1524073,
umls-concept:C1548799,
umls-concept:C1554080,
umls-concept:C1705248,
umls-concept:C1706198,
umls-concept:C1880022,
umls-concept:C1947951
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pubmed:issue |
10
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pubmed:dateCreated |
2010-6-14
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pubmed:abstractText |
The cytochrome c maturation process is carried out in the bacterial periplasm, where some specialized thiol-disulfide oxidoreductases work in close synergy for the correct reduction of oxidized apocytochrome before covalent heme attachment. We present a structural and functional characterization of the soluble periplasmic domain of CcmG from the opportunistic pathogen P. aeruginosa (Pa-CcmG), a component of the protein machinery involved in cyt c maturation in gram-negative bacteria. X-ray crystallography reveals that Pa-CcmG is a TRX-like protein; high-resolution crystal structures show that the oxidized and the reduced forms of the enzyme are identical except for the active-site disulfide. The standard redox potential was calculated to be E(0') = -0.213 V at pH 7.0; the pK(a) of the active site thiols were pK(a) = 6.13 +/- 0.05 for the N-terminal Cys74 and pK(a) = 10.5 +/- 0.17 for the C-terminal Cys77. Experiments were carried out to characterize and isolate the mixed disulfide complex between Pa-CcmG and Pa-CcmH (the other redox active component of System I in P. aeruginosa). Our data indicate that the target disulfide of this TRX-like protein is not the intramolecular disulfide of oxidized Pa-CcmH, but the intermolecular disulfide formed between Cys28 of Pa-CcmH and DTNB used for the in vitro experiments. This observation suggests that, in vivo, the physiological substrate of Pa-CcmG may be the mixed-disulfide complex between Pa-CcmH and apo-cyt.
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Aug
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pubmed:issn |
1097-0134
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pubmed:author |
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pubmed:copyrightInfo |
(c) 2010 Wiley-Liss, Inc.
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pubmed:issnType |
Electronic
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pubmed:day |
1
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pubmed:volume |
78
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
2213-21
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pubmed:meshHeading |
pubmed-meshheading:20544959-Bacterial Proteins,
pubmed-meshheading:20544959-Catalytic Domain,
pubmed-meshheading:20544959-Crystallography, X-Ray,
pubmed-meshheading:20544959-Cytochromes c,
pubmed-meshheading:20544959-Enzyme Stability,
pubmed-meshheading:20544959-Kinetics,
pubmed-meshheading:20544959-Membrane Proteins,
pubmed-meshheading:20544959-Models, Molecular,
pubmed-meshheading:20544959-Mutant Proteins,
pubmed-meshheading:20544959-Oxidation-Reduction,
pubmed-meshheading:20544959-Periplasmic Proteins,
pubmed-meshheading:20544959-Protein Disulfide Reductase (Glutathione),
pubmed-meshheading:20544959-Protein Interaction Domains and Motifs,
pubmed-meshheading:20544959-Protein Structure, Tertiary,
pubmed-meshheading:20544959-Pseudomonas aeruginosa,
pubmed-meshheading:20544959-Recombinant Fusion Proteins,
pubmed-meshheading:20544959-Solubility,
pubmed-meshheading:20544959-Thioredoxins
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pubmed:year |
2010
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pubmed:articleTitle |
Structural and functional characterization of CcmG from Pseudomonas aeruginosa, a key component of the bacterial cytochrome c maturation apparatus.
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pubmed:affiliation |
Dipartimento di Scienze Biochimiche, Istituto di Biologia e Patologia Molecolari del CNR, Sapienza-Università di Roma, Piazzale A. Moro 5, 00185, Roma, Italy.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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