Relaxometry of paramagnetic liposomes
S.H. Koenig
Investigative Radiology
We report the magnetic field dependence of 1/T1 of solvent water protons and deuterons (nuclear magnetic relaxation dispersion, or NMRD, profiles) for solutions of steer lens beta L-crystallin. Such data allow the study of intermolecular protein interactions over a wide concentration range, here 1–34% vol/vol, by providing a measure of the rotational relaxation time of solute macromolecules. We conclude that, for approximately less than 5% protein, the solute particles are noncompact, with a rotationally averaged volume approximately three times that of a compact 60-kD sphere. (Earlier results for alpha-crystallin, approximately 1,000 kD, from optical and osmotic measurements (Vérétout and Tardieu, 1989. J. Mol. Biol. 205:713–728), show a similar, approximately twofold, effect). At intermediate concentrations, to approximately 20% protein, there is evidence for limited association or oligomerization, as found for the structurally related gamma II-crystallin (Koenig et al. 1990. Biophys. J. 57:461–469), to a limiting size about two-thirds that of alpha-crystallin. The difference in NMRD behavior of the three classes of crystallins is consonant with their differing osmotic properties (Vérétout and Tardieu. J. Mol. Biol. 1989, 205:713–728; Kenworthy, McIntosh, and Magid. Biophys. J. 1992. 61; Tardieu et al. 1992. Eur. Biophys. J. 21:1–12). We indicate how the unusual structures and interactions of these three classes of proteins can be combined to optimize transparency and minimize colloid osmotic difficulties in eye lens. © 1993, The Biophysical Society. All rights reserved.
S.H. Koenig
Investigative Radiology
S.H. Koenig, Q.F. Ahkong, et al.
Farmacevtski Vestnik
S.H. Koenig, R.D. Brown, et al.
Magnetic Resonance in Medicine
S.H. Koenig
Proceedings of the Physical Society