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The hydrophobic region of signal peptides is involved in the interaction with membrane-bound SecA.
Mori, H; Araki, M; Hikita, C; Tagaya, M; Mizushima, S.
Afiliação
  • Mori H; School of Life Science, Tokyo University of Pharmacy and Life Science, Hachioji, Japan.
Biochim Biophys Acta ; 1326(1): 23-36, 1997 May 22.
Article em En | MEDLINE | ID: mdl-9188797
The positive charges of signal peptides are important for the interaction with SecA, a translocation ATPase. To examine whether or not the hydrophobic region of signal peptides also interacts with SecA, we constructed model preproteins, proOmpF-Lpps, possessing no positively charged amino acid residues at the amino-terminus and different numbers of alanine/leucine residues in the hydrophobic region of signal peptides. When the hydrophobic stretch was sufficiently long, amino-terminal positively charged residues were not required for the translocation of preproteins across the cytoplasmic membrane of Escherichia coli both in vitro and in vivo. Chemical cross-linking between SecA and preproteins possessing no positively charged residues at the amino-terminus was observed only in the presence of liposomes containing acidic phospholipids. The degree of cross-linking increased as the length of the hydrophobic stretch increased irrespective of whether positively charged residues were present or not. A preprotein possessing no positively charged residues at the amino-terminus, which is competent in the presence of liposomes, competitively inhibited the cross-linking of wild-type proOmpF-Lpp with SecA under the same conditions. It is concluded that both the amino-terminal positive charges and central hydrophobic domains are involved in the interaction with SecA in the initial stage of translocation in addition to their possible roles in transmembrane movement of preproteins.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Proteínas de Membrana Transportadoras / Proteínas de Bactérias / Proteínas Recombinantes / Sinais Direcionadores de Proteínas / Membrana Celular / Adenosina Trifosfatases / Proteínas de Escherichia coli Idioma: En Revista: Biochim Biophys Acta Ano de publicação: 1997 Tipo de documento: Article País de afiliação: Japão País de publicação: Holanda
Buscar no Google
Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Proteínas de Membrana Transportadoras / Proteínas de Bactérias / Proteínas Recombinantes / Sinais Direcionadores de Proteínas / Membrana Celular / Adenosina Trifosfatases / Proteínas de Escherichia coli Idioma: En Revista: Biochim Biophys Acta Ano de publicação: 1997 Tipo de documento: Article País de afiliação: Japão País de publicação: Holanda