Abstract
The fluorescent unnatural amino acid, (7-hydroxycoumarin-4-yl)ethylglycine (HC), was site-specifically incorporated at the Phe69 site, close to the entrance of the selectivity filter of the NaK channel. Decreased fluorescence lifetime and elevated time-resolved anisotropy of NaK-F69HC in buffers with high K(+)/Na(+) molar ratios indicated the K(+) preference at the entrance of the NaK channel, consistent with previous crystal structure results of the NaK channel.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Bacillus cereus
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Bacterial Proteins / physiology*
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Bacterial Proteins / ultrastructure
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Fluorescence Polarization*
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Glycine / analogs & derivatives*
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Glycine / chemistry
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Glycine / genetics
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Mutagenesis, Site-Directed
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Potassium / physiology*
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Potassium Channels / physiology*
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Potassium Channels / ultrastructure
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Umbelliferones / chemistry*
Substances
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(7-hydroxycoumarin-4-yl) ethylglycine
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Bacterial Proteins
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Potassium Channels
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Umbelliferones
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prokaryotic potassium channel
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Potassium
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Glycine