TABLE 1.

D/H-exchange kinetics in isotropic solution

Peptide	Dmax*	Dobs†	D0‡	D24§	kA [min−1]¶	kB [min−1]‖	kC [min−1]**
syx	41	38.8 ± 1.8	15.9 ± 0.3	ND††	—‡‡	0.688 ± 0.483	0.0306 ± 0.0028
syb-wt	40	39.0 ± 0.3	15.5 ± 1.1	0.2 ± 0.4	12.6 ± 6.9	0.365 ± 0.114	0.0109 ± 0.0008
syb-multA	39	38.4 ± 0.1	15.9 ± 0.7	0.2 ± 0.1	9.0 ± 4.2	0.556 ± 0.213	0.0104 ± 0.0032
syb-L8	39	38.4 ± 0.2	17.0 ± 0.6	0.5 ± 0.5	1.8 ± 0.35	0.033 ± 0.004	0.0019 ± 0.0006
L16	38	36.9 ± 0.5	16.5 ± 0.1	1.6 ± 1.6	1.6 ± 0.11	0.015 ± 0.001	0.0011 ± 0.0005

^*D_max is the calculated number of labile hydrogens/deuteriums.

^†D_obs is the number of deuteriums on the peptides upon exhaustive deuteration as determined from the mass increases of the triply charged ions.

^‡D₀ is the number of deuteriums that do not exchange under stop conditions (pH 2.5, on ice).

^§D₂₄ is the number of deuteriums that remain after 24 h incubation under exchange conditions (2 min at pH 7.4, 20°C).

^¶k_A is the exchange rate constant of deuterium population A (= 9) exchanging with fast kinetics.

^‖k_B is the exchange rate constant of deuterium population B (= 4) exchanging with intermediate kinetics.

^**k_C is the exchange rate constant of deuterium population C (= 6) exchanging with slow kinetics.

^††ND is Not Determined.

^‡‡The k_A value of syx is at least as high as that of syb, but could not be precisely calculated due to improper curve fitting at the earliest time points.