A strategic protein in cytochrome c maturation: three-dimensional structure of CcmH and binding to apocytochrome c. (Articolo in rivista)

Type
Label
  • A strategic protein in cytochrome c maturation: three-dimensional structure of CcmH and binding to apocytochrome c. (Articolo in rivista) (literal)
Anno
  • 2007-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1074/jbc.M702702200 (literal)
Alternative label
  • Di Matteo A, Gianni S, Schininà ME, Giorgi A, Altieri F, Calosci N, Brunori M, Travaglini-Allocatelli C. (2007)
    A strategic protein in cytochrome c maturation: three-dimensional structure of CcmH and binding to apocytochrome c.
    in The Journal of biological chemistry (Print)
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Di Matteo A, Gianni S, Schininà ME, Giorgi A, Altieri F, Calosci N, Brunori M, Travaglini-Allocatelli C. (literal)
Pagina inizio
  • 27012 (literal)
Pagina fine
  • 27019 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 282 (literal)
Rivista
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Univ Rome, Dipartimento Sci Biochim & Ist Biol & Patol Mol C, Piazzale A Morro 5, I-00815 Rome, Italy. (literal)
Titolo
  • A strategic protein in cytochrome c maturation: three-dimensional structure of CcmH and binding to apocytochrome c. (literal)
Abstract
  • CcmH ((c) under bar ytochromes (c) under bar (m) under bar aturation protein H) is an essential component of the assembly line necessary for the maturation of c-type cytochromes in the periplasm of Gram-negative bacteria. The protein is a membrane-anchored thiol-oxidoreductase that has been hypothesized to be involved in the recognition and reduction of apocytochrome c, a prerequisite for covalent heme attachment. Here, we present the 1.7 angstrom crystal structure of the soluble periplasmic domain of CcmH from the opportunistic pathogen Pseudomonas aeruginosa (Pa-CcmH*). The protein contains a three-helix bundle, i.e. a fold that is different from that of all other thiol-oxidoreductases reported so far. The catalytic Cys residues of the conserved LRCXXC motif (Cys(25) and Cys(28)), located in a long loop connecting the first two helices, form a disulfide bond in the oxidized enzyme. We have determined the pK(a) values of these 2 Cys residues of Pa-CcmH* ( both > 8) and propose a possible mechanistic role for a conserved Ser(36) and a water molecule in the active site. The interaction between Pa-CcmH* and Pa-apocyt c(551) ( where cyt c(551) represents cytochrome c(551)) was characterized in vitro following the binding kinetics by stopped-flow using a Trp-containing fluorescent variant of Pa-CcmH* and a dansylated peptide, mimicking the apocytochrome c551 heme binding motif. The kinetic results show that the protein has a moderate affinity to its apocyt substrate, consistent with the role of Pa-CcmH as an intermediate component of the assembly line for c-type cytochrome biogenesis. (literal)
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