All data were recorded on a U-13C, U-15N labeled W60G β 2m sample 0.5 mM in phosphate buffer 70 mM, NaCl 100 mM, pH 6.6, at 310K with a Bruker Avance 500 and with a Varian INOVA spectrometers operating at proton frequency of 500 and 800 MHz, respectively. Proton chemical shifts were referenced to 2,2-Dimethyl-2-silapentane-5-sulfonate sodium salt, DSS, whose resonance was set to 0.0 ppm. 13C and 15N chemical shifts were referenced indirectly to DSS, using absolute frequency ratio51 (link). Sequence specific assignment were achieved using [1H, 15N]-HSQC and [1H, 13C]-HSQC together with 3D triple-resonance experiments, in particular by using the [15N, 1H]- HNCA/[15N, 1H]- HN(CO)CA for the identification of patterns of sequentially linked spin systems and 3D [15N, 1H]- HNCACB/[15N, 1H]-HN(CO)CACB pair of experiments, which allowed the identification of the amino acid types. 3D (H)CCH-TOCSY was used for the assignment of Hα and Hβ resonances.
The spectra were processed with Topspin 2.0 (Bruker Biospin) and analysed into the Sparky (T. D. Goddard and D. G. Kneller, SPARKY3, University of California, San Francisco) framework.
The spectra were processed with Topspin 2.0 (Bruker Biospin) and analysed into the Sparky (T. D. Goddard and D. G. Kneller, SPARKY3, University of California, San Francisco) framework.