Table 1.

Deviation between experimental NMR PRE intensity ratios and values back-calculated from the crystal structure of CylR2 55R1 for different conformations of the MTSL tag in T4L 72R1 (Sezer et al. 2009), T4L 131R1 (Sezer et al. 2009) and CylR2 55R1 (this work)

Protein/conformers	Angle (degree)					χ2
	χ1	χ2	χ3	χ4	χ5
T4L 72R1
C1	−176	49	93	− 82	100	2.26
C2	−168	48	85	−159	−70	3.54
C3	−169	48	78	−144	20	3.44
C4	−63	−66	94	172	57	3.91
C5	−55	−44	−91	−178	−93	3.51
T4L 131R1a
C1	−173	173	−96	72	−100	2.10
C2	−62	−48	101	−161	77	4.68
C3	−171	66	−97	174	−63	3.96
C4	−65	−177	−84	−174	−87	7.69
C5	−58	−58	97	173	−83	4.27
CylR2 55R1
Chain A/C1	−63	−61	−87	−77	161	0.76b
Chain B/C2	−74	−53	−97	−72	156

^aConformations observed in the crystal structure of T4 lysozyme 131R1 are underlined (Sezer et al. 2009)

^bAverage χ² value obtained for the two subunits of the CylR2 dimer