BIOINORGANIC CHEMISTRY A Short Course Second Edition

exposed surface of the voltage sensor, while arg300 and arg303 interact with

acidic residues on helices S1 and S2 inside the voltage sensor. The authors

believe that the energetic balance between the just - described electrostatic and

hydrophobic forces is very important for voltage sensor function.

This section on describing potassium channels has relied heavily on struc-

tural analyses and ensuing models based on X - ray crystallographic studies. It

must be remembered that all X - ray structures are static snapshots capturing

a protein, or any other molecule, in one conformation. As the discussions of

potassium ion voltage - dependent channels above has indicated, structural

snapshots can lead to lengthy discussions of native versus non - native protein

conformations and the relevance of any given protein structure to the function

of said protein. Consequently, the reader should be on the lookout for new

information sure to be published in the primary literature concerning potas-

sium ion channels in the future.

5.5 Conclusions,

Chapter 5 has introduced topics in metal and nonmetal ion homeostasis,

concentrating on Groups I and II metal ions. Some biomolecules containing

potassium (and sodium) ions have been described in detail, especially

the sodium/potassium ion pump and voltage - gated potassium channels.

Potassium ion channels are therapeutic targets in autoimmune and some neu-

rodegenerative diseases and thus are of interest to bioinorganic chemists. To

design drug molecules that would successfully target these biomolecules,

researchers must understand their three - dimensional structure; thus the

emphasis here has been on the X - ray crystallographic studies that have strived

toward that goal.

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7. Tu , S. - M. ; Delpassand , E. S. ; Jones , D. ; Amato , R. J. ; Ellerhorst , J. ; Logothetis , C. J.
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