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. Author manuscript; available in PMC: 2015 May 5.
Published in final edited form as: Chembiochem. 2014 Apr 1;15(7):995–1000. doi: 10.1002/cbic.201300729

Table 1.

NMR diffusion measurements with [80%-2H,u-15N]-OmpA in DMPC nanodiscs and Fos-10 micelles, T = 313 K.

Sample Dt (10−11 m2 s−2)[a] Dr (106 s−1)[b] Rh (nm)[c]
0.5 mM OmpA/nanodiscs before TEV-cleavage 6.0 ± 0.2 (proteins)[d]
6.3 ± 0.2 (lipid)
2.0 ± 0.2 4.8 ± 0.1
0.3 mM OmpA/nanodiscs after TEV-cleavage 6.9 ± 0.2 (proteins)[d]
7.1 ± 0.2 (lipid)
2.4 ± 0.2 4.7 ± 0.1
0.4 mM ‘empty’ nanodiscs 6.6 ± 0.2 (scaffold protein)
6.3 ± 0.2 (lipid)
- -
1.0 mM OmpA/Fos-10 before TEV-cleavage 8.6 ± 0.2 (protein)
15.1 ± 0.2 (detergent) [e]
7.3 ± 0.2 3.0 ± 0.1
[a]

Determined using 1H-TRO-STE NMR experiments.[26] Self-diffusion constants were obtained independently from measurements of the integral over the protein signals between 7.7 and 9.0 ppm (Figure S1), and of the integrals of three lipid or detergent resonances, respectively, between 0.0 and 2.0 ppm (Figure S2).

[b]

Determined with the 1D TRACT NMR experiment.[27]

[c]

Rh = (3Dt/4Dr)1/2

[d]

In the OmpA nanodiscs the contributions from the unlabeled scaffold protein and the 2H,15N-labeled OmpA are superimposed, but could be separated with the use of a 15N-filter. Within the experimental accuracy, observation of the individual protein components and their sum yielded identical results.

[e]

The self-diffusion constant obtained with observation of detergent NMR lines (Figure S2) is larger than for the protein, due to averaging of the contributions from monomeric detergent molecules, empty detergent micelles and OmpA-containing micelles.[22]