Copper(I) stabilization by cysteine/tryptophan motif in the extracellular domain of Ctr4.
J Inorg Biochem
; 159: 45-9, 2016 06.
Article
em En
| MEDLINE
| ID: mdl-26908286
ABSTRACT
Copper transporter Ctr4 of fission yeast has a quasi-palindromic sequence rich in cysteine and aromatic amino acid residues, CX4YWNWYX4C (where X represents any amino acid), in the N-terminal extracellular domain. A 24-mer peptide comprising this sequence is bound to Cu(I) through the cysteine thiolate coordination. Luminescence, UV absorption and resonance Raman spectra of the Cu(I)-peptide complex show that at least one of the two tryptophan side chains is located in close proximity to the thiolate-Cu(I) center and interacts with the Cu(I) ion via π-electrons of the indole ring. Although the thiolates and Cu(I) are oxidized to disulfide and Cu(II), respectively, only very slowly in air-saturated solutions, replacements of the tryptophan residues to phenylalanine significantly accelerate the oxidation reactions. The results obtained indicate that the interaction between Cu(I) and tryptophan via π-electrons plays a significant role in protecting the thiolate-Cu(I) center against the oxidation. The cysteine- and tryptophan-rich quasi-palindromic sequence may be a metal binding motif that stabilizes Cu(I) in the oxidizing extracellular environment.
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Coleções:
01-internacional
Temas:
Geral
Base de dados:
MEDLINE
Assunto principal:
Schizosaccharomyces
/
Cobre
/
Proteínas de Transporte de Cátions
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Proteínas de Schizosaccharomyces pombe
Idioma:
En
Revista:
J Inorg Biochem
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Japão