Abstract:
:A new general method for the determination of electrostatic potentials at biological surfaces is presented. The approach is based on measurement of the collision frequency of a charged nitroxide in solution with a nitroxide fixed to the surface at the point of interest. The collision frequency is determined with 14N:15N double label electron-electron double resonance (ELDOR). As a test, the method is shown to give values for phospholipid bilayer surface potentials consistent with the Gouy-Chapman theory, a simple model shown by many independent tests to accurately describe charged, planar surfaces. In addition, the method is applied to determine the electrostatic potential near the surface of DNA. The results indicate that the potential is significantly smaller than that predicted from Poisson-Boltzmann analysis, but is in qualitative agreement with that predicted by Manning's theory of counter ion condensation. The method is readily extended to measurement of surface potentials of proteins.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Shin YK,Hubbell WLdoi
10.1016/S0006-3495(92)81950-1subject
Has Abstractpub_date
1992-06-01 00:00:00pages
1443-53issue
6eissn
0006-3495issn
1542-0086pii
S0006-3495(92)81950-1journal_volume
61pub_type
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