Table 1.

Hydrogen exchange rate constants of the imino protons, k_ex, for Macugen free and in the HBD-Macugen and VEGF-Macugen complexes (s⁻¹)

Base Pair	Imino proton	Free Macugen	HBD-Macugen		VEGF-Macugen
		15 °C	15 °C	35 °C	35 °C
G1·C27	G27	76 ± 5	16 ± 5	>400a	>400a
G2·C26	G2	≤2.1b	<1.5c,d	<1.5c,d	<1.5c,d
G3·C25	G3	≤2.1b	<1.5c	<1.5c	<1.5c
A4·U24	U24	>400a	4.2 ± 0.5	33 ± 2	20 ± 4
n. d. f	U20	>400a	>400a	>400a	44 ± 5
U6·A19	U6	>400a	2.7 ± 0.5	48 ± 3	29 ± 8
C7·U18	U18	>400a	<1.5c,e	16 ± 1	8 ± 3
A8·U17	U17	>400a	<1.5c	<1.5c	<1.5c
G9·C16	G9	9.0 ± 0.6	<1.5c,e	<1.5c	<1.5c
U10·G15	U10	32 ± 2	<1.5c,d	<1.5c,d	<1.5c,d
	G15	25 ± 1	<1.5c	<1.5c	<1.5c

^aNo resonances were observed for these imino protons under these conditions. Simulated two-site chemical exchange of the imino protons with water yielded a lower limit of 400 s⁻¹ for these exchange rates (data not shown).

^bThe G2 and G3 resonances overlap and only an upper limit for each proton is reported.

^cOnly an upper limit of k_ex < 1.5 s⁻¹ is reported due to a potential NOE with water interfering with measurement of the exchange rate (see text).

^dThe G2 and U10 resonances overlap and only an upper limit on the k_ex for each proton is reported.

^eThe G9 and U18 resonances overlap and only an upper limit on the k_ex for each proton is reported.

^fThe base pair for U20 was not determined.