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. 2010 May 19;98(9):1801-8.
doi: 10.1016/j.bpj.2010.01.028.

Metal-assisted channel stabilization: disposition of a single histidine on the N-terminus of alamethicin yields channels with extraordinarily long lifetimes

Daisuke Noshiro  1 , Koji Asami, Shiroh Futaki
Affiliations

Metal-assisted channel stabilization: disposition of a single histidine on the N-terminus of alamethicin yields channels with extraordinarily long lifetimes

Daisuke Noshiro et al. Biophys J. .

Abstract

Alamethicin, a member of the peptaibol family of antibiotics, is a typical channel-forming peptide with a helical structure. The self-assembly of the peptide in the membranes yields voltage-dependent channels. In this study, three alamethicin analogs possessing a charged residue (His, Lys, or Glu) on their N-termini were designed with the expectation of stabilizing the transmembrane structure. A slight elongation of channel lifetime was observed for the Lys and Glu analogs. On the other hand, extensive stabilization of certain channel open states was observed for the His analog. This stabilization was predominantly observed in the presence of metal ions such as Zn(2+), suggesting that metal coordination with His facilitates the formation of a supramolecular assembly in the membranes. Channel stability was greatly diminished by acetylation of the N-terminal amino group, indicating that the N-terminal amino group also plays an important role in metal coordination.

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Figures

Figure 1
Figure 1
(A) Design of ALM analogs with a charged amino acid on their N-termini. Abbreviations: U, Aib; Pheol, phenylalaninol; Ac, acetyl; NH2, free amino terminus. (B) Schematic representation of channel formation of the N-terminally modified analogs in the membrane.
Figure 2
Figure 2
Typical channel current records of ALM (A), NH2-HG-ALM (B), NH2-KG-ALM (C), and NH2-EG-ALM (D). Note that a different timescale was employed for each channel record. The conductance histograms are shown to the right of the respective records. Voltage: 120 mV; electrolyte: 1 M KCl containing 10 mM HEPES (pH 7.0); peptide concentration: 20 nM. The conductance levels of ALM (A) are numbered from 1 to 7 in the order of increasing conductance, and those of NH2-HG-ALM (B) are analogously allotted to levels 4′–8′.
Figure 3
Figure 3
A typical channel current record of NH2-HG-ALM in the presence of 100 μM EDTA and the conductance histogram. Voltage: 120 mV; electrolyte: 1 M KCl containing 10 mM HEPES (pH 7.0); peptide concentration: 20 nM.
Figure 4
Figure 4
Channel current records of NH2-HG-ALM in the presence of 100 μM EDTA and 200 μM ZnCl2, and the conductance histograms. Electrolyte: 1 M KCl containing 10 mM HEPES (pH 7.0); peptide concentration: 20 nM.
Figure 5
Figure 5
(A) Structure of N-terminally linked ALM by a disulfide bond (di-ALM). (B) Conductance histograms calculated from channel current records of ALM (black), di-ALM (red), and NH2-HG-ALM (blue) in the presence of 100 μM EDTA and 200 μM ZnCl2, respectively. Voltage: 120 mV; electrolyte: 1 M KCl containing 10 mM HEPES (pH 7.0).
Figure 6
Figure 6
(A) Channel current records of NH2-HG-ALM in the presence of (i) 100 μM EDTA and 150 μM ZnCl2, and after the addition of (ii) 300 μM EDTA, (iii) 400 μM ZnCl2, and (iv) 600 μM EDTA. Voltage: 80 mV; electrolyte: 1 M KCl containing 10 mM HEPES (pH 7.0); peptide concentration: 20 nM. (B) Mean channel current and the standard deviations calculated from the recordings for 30 s.
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References

    1. Woolley G.A., Lougheed T. Modeling ion channel regulation. Curr. Opin. Chem. Biol. 2003;7:710–714. - PubMed
    1. Sakai N., Mareda J., Matile S. Rigid-rod molecules in biomembrane models: from hydrogen-bonded chains to synthetic multifunctional pores. Acc. Chem. Res. 2005;38:79–87. - PubMed
    1. Bayley H., Jayasinghe L. Functional engineered channels and pores (Review) Mol. Membr. Biol. 2004;21:209–220. - PubMed
    1. Gokel G.W., Schlesinger P.H., Weber M.E. Functional, synthetic organic chemical models of cellular ion channels. Bioorg. Med. Chem. 2004;12:1291–1304. - PubMed
    1. Futaki S. Peptide ion channels: design and creation of function. Biopolymers. 1998;47:75–81. - PubMed

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