Table 2. NMR experimental parameters

NMR experiment	Field (MHz)	F1: (ni; sw; at)	F2: (ni; sw; at)	F3: (ni; sw; at)	F4: (ni; sw; at)	Scans; rd(s); mixing time, ms; total time, hr
4D 1Hm-13Cm-13Cm-1Hm HMQC-NOESY-HMQC(1-3)†	800	1Hm: 26*; 960 Hz; 27 ms	13Cm: 48*; 2211 Hz; 22 ms	13Cm: 36*; 2211 Hz; 16 ms	1Hm: 768*; 12001 Hz; 64 ms	4; 1.0; 175; 158.
4D 1Hm-13Cm-15N-1HN HMQC-NOESY-TROSY(4)	800	1Hm: 20*; 1200 Hz; 16 ms	13Cm: 32*; 3600 Hz; 8.5 ms	15N: 36*; 2268 Hz; 15 ms	1HN: 767*; 12001 Hz; 64 ms	2; 1.25; 175; 158.
4D 1HN-15N-15N-1HN HSQC-NOESY-TROSY)(5)‡	800	1HN: 20*; 3600 Hz; 5.5 ms	15N: 20*; 2268 Hz; 8.5 ms	15N: 32*; 2268 Hz; 14 ms	1HN: 817*; 12775 Hz; 64 ms	4; 1.40; 90; 183.
3D (1Hm)-13Cm-13Cm-1Hm HMQC-NOESY-HMQC(6)	800	13Cm: 80*; 2211 Hz; 36 ms	13Cm: 80*; 2211 Hz; 36 ms	1Hm: 768*; 12001 Hz; 64 ms		12; 1.0; 150; 109.
3D 1Hm-13Cm-1Hm HMQC-NOESY(7)§	800	1Hm: 40*; 960 Hz; 41 ms	13Cm: 80*; 2211 Hz; 36 ms	1Hm: 675*; 12001 Hz; 64 ms		24; 1.0; 150; 108.
3D (1HN)-15N-15N-1HN HSQC-NOESY-TROSY(8)	600	15N: 32*; 1638 Hz; 19 ms	15N: 76*; 1638 Hz; 46 ms	1HN: 675*; 10000 Hz; 67 ms		16; 1.85;200; 95.
3D 1HN-15N-1HN NOESY-TROSY(8)	600	1HN: 32*; 2400 Hz; 13 ms	15N: 76*; 1638 Hz; 46 ms	1HN: 675*; 10000 Hz; 67 ms		16; 1.85;200; 94.
3D (1Hm)-13Cm-15N-1HN HMQC-NOESY-TROSY	600	13Cm: 42*; 1660 Hz; 25 ms	15N: 76*; 1638 Hz; 46 ms	1HN: 675*; 10000 Hz; 67 ms		16; 1.30;200; 93.
3D 1Hm-(13Cm)-15N-1HN HMQC-NOESY-TROSY	600	1Hm: 18*; 780 Hz; 22 ms	15N: 76*; 1638 Hz; 46 ms	1HN: 680*; 10000 Hz; 68 ms		32; 1.50;200; 89.

All NMR experiments were performed at 37°C on either a Varian Inova 800 MHz spectrometer equipped with a room-temperature pulsed-field gradient triple resonance probe or on a Varian Inova 600 MHz spectrometer equipped with a cryogenically cooled probe. For each dimension of every experiment, the following parameters are listed: type of nucleus evolved, total number of acquired points, ni, (* - complex points), sweep width in Hz (sw), and maximum acquisition time (at) in ms. In addition, the spectrometer field, the number of scans/FID, relaxation delay (rd), NOE mixing time (ms) and the total experimental acquisition time (hr.) are listed for each experiment. The nuclei whose chemical shifts are not evolved are parenthesized in the names of the experiments. Subscript "m" denotes the corresponding chemical shifts of methyl groups.

^†Experiment was recorded using non-linear (sparse) sampling in F₁,F₂, and F₃ (2) and reconstructed with a multidimensional decomposition (MDD) algorithm (9);» 30% of the data that would be acquired in a ‘normal’ 4D data set (linear acquisition) was obtained using sparsing.

^‡The same experiment was used previously for sequential assignments of MSG backbone resonances (1); "TROSY" in the names of NMR experiments implies the use of single- transition-to-single transition transfer scheme with gradient coherence selection (10).

^§Experiment was recorded with the NOE mixing period immediately preceding the acquisition period and ¹H_m chemical shifts recorded in the F₁ dimension during the evolution of ¹H-¹³C multiple-quantum coherence.

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