TABLE 1.

Tumbling properties of free and connected B. stearothermophilus IF2-C1 and IF2-C2 domains

For isolated and connected IF2-C1 and -C2 domains, NMR relaxation data were analyzed by Modelfree analysis. Extracted rotational correlation times and diffusion tensors were compared with predictions based on structure models.

Domain	C1	C1-C2a	C1-C2b	C2
Rotational correlation times τc (ns)
Predictedc	5.19	18.4	18.4	6.95
Experimental	9.02 ± 0.04	11.59 ± 0.07	11.44 ± 0.05	7.34 ± 0.03
Rotational diffusion tensor axis length ratios
Predictedc,d
Dxx/Dzz	0.94	0.40	0.40	0.75
Dyy/Dzz	0.98	0.40	0.40	0.83
Experimentale
Dxx/Dzz	0.73 ± 0.02	0.85 ± 0.03	0.84 ± 0.02	0.80 ± 0.02

^a Domain C1 is considered when connected to domain C2.

^b Domain C2 is considered when connected to domain C1.

^c Predictions were done with HYDRONMR on lowest energy NMR structures of isolated IF2-C1 and IF2-C2 and on the homology model of connected IF2 C1-C2.

^d Assumed is: D_zz > D_yy ≥ D_xx.

^e Model-free analyses were performed with FAST-Modelfree assuming axial symmetry (D_xx = D_yy, hence η = 0).