An anion-selective analogue of the channel-forming peptide alamethicin.
Biochemistry
; 38(19): 6144-50, 1999 May 11.
Article
em En
| MEDLINE
| ID: mdl-10320341
ABSTRACT
The peptide alamethicin self-assembles to form helix bundle ion channels in membranes. Previous macroscopic measurements have shown that these channels are mildly cation-selective. Models indicate that a source of cation selectivity is a zone of partial negative charge toward the C-terminal end of the peptide. We synthesized an alamethicin derivative with a lysine in this zone (replacing the glutamine at position 18 in the sequence). Microscopic (single-channel) measurements demonstrate that dimeric alamethicin-lysine18 (alm-K18) forms mildly anion-selective channels under conditions where channels formed by the parent peptide are cation-selective. Long-range electrostatic interactions can explain the inversion of ion selectivity and the conductance properties of alamethicin channels.
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Base de dados:
MEDLINE
Assunto principal:
Alameticina
/
Canais Iônicos
Idioma:
En
Ano de publicação:
1999
Tipo de documento:
Article