TABLE 2.

RDC R-factors for IIB^Chb

	RDC R-factor (%)a
	X-ray	NMR	NMR
	IIBChb(C10S)b	IIBChb(C10S)b	phospho-IIBChbb
1DNH RDCs measured on free IIBChb(C10S)c
100 mm NaCl and 10 mg/ml pf1
All data (73)/excluding residues 9–16 (67)	12.1/8.0	44.7/43.8	18.8/14.4
Active site loop (residues 9–16) (6)d	70.1	79.5	88.2
400 mm NaCl and 17 mg/ml pf1
All data (80)/excluding residues 9–16 (74)	14.7/8.4	40.2/34.8	16.2/11.5
Active site loop (residues 9–16) (6)d	50.9	88.4	50.2
1DNH RDCs measured on free phospho-IIBChbc
100 mm NaCl and 10 mg/ml pf1
All data (66)/excluding residues 9–16 (59)	38.8/16.8	55.4/49.3	19.9/20.8
Active site loop (residues 9–16) (7)e	73.2	70.0	15.5
200 mm NaCl and 15 mg/ml pf1
All data (76)/excluding residues 9–16 (69)	34.1/16.0	52.2/46.6	16.6/16.8
Active site loop (residues 9–16) (7)e	70.6	70.9	15.3

^a The RDC R-factor is defined as 100×[<(D_obs − D_calc)²>/2<D_obs²>)]^1/2 (71), where D_obs are the observed RDCs, and D_calc are the calculated RDCs obtained by singular value decomposition against the coordinates of the indicated protein (72). The values for the magnitude of the principal component of the alignment tensor (D_a^NH) and the rhombicity (η) are as follows. For the RDCs measured on free IIB^Chb(C10S), the values are 25.6 Hz and 0.4, respectively, in 100 mm NaCl and 10 mg/ml pf1, and −8.9 Hz and 0.3, respectively, in 400 mm NaCl and 17 mg/ml phage pf1; the normalized scalar product between the alignment tensors (80) at the two salt concentrations is −0.1, indicating that the two alignment tensors are effectively independent of one another. For the RDCs measured on free phospho-IIB^Chb, the values are 21.2 Hz and 0.53, respectively in 100 mm NaCl and 10 mg/ml phage pf1, and −9.6 Hz and 0.64, respectively in 200 mm NaCl and 15 mg/ml phage pf1, with a normalized scalar product of 0.96 between the two alignment tensors.

^b The PDB accession codes are 1IIB and 1E2B for the x-ray (9) and NMR (10) structures of IIB^Chb(C10S), respectively; and 1H9C for the NMR structure of phospho-IIB^Chb (11). The active site residue is located at position 10, and the active site loop comprises residues 9–16.

^c The number of experimentally measured ¹D_NH RDCs is shown in parentheses.

^d RDCs were measured for residues 9, 10, 11, 12, 13, and 16. The cross-peaks for the backbone amide groups of Met-14 and Ser-15 were too broad to permit measurement of the ¹J_NH splitting in the alignment media.

^e RDCs were measured for residues 9, 10, 11, 12, 13, 14, and 16. The cross-peak for the backbone amide group of Ser-15 was too broad to permit measurement of the ¹J_NH splitting in the alignment medium.