Skip to main content
. Author manuscript; available in PMC: 2008 Dec 9.
Published in final edited form as: Biochemistry. 2008 Sep 17;47(40):10564–10575. doi: 10.1021/bi801313y

Table 1.

Step-wise zinc binding affinities, KZni, derived from mag-fura-2 and quin-2 chelator competition experimentsa

BxmR protein chelator KZn1 (M−1) KZn2 (M−1) KZn3 (M−1) KZn4 (M−1)
wild-type mag-fura-2 ≥109 a ≥109 2.2 × 107 n.d.b
quin-2 9.4 × 1012 1.1 × 1012 n.d.c n.d.c
α3NΔ mag-fura-2 ≥109 a 6.0 × 107 – –
quin-2 6.4 × 1012 n.d.c – –
α5Δ mag-fura-2 ≥109 a 3.0 × 106 – –
quin-2 4.6 × 1010 n.d.c – –
a

From nonlinear least-squares fits to data like those shown in Fig. 2 to a model assuming four (wild-type) or two (α3NΔ and α5Δ) stepwise binding events to a nondissociable dimer, each characterized by an affinity of KZni.

b

n.d., binding not detected, or KZni≤105 M−1 (a lower limit for mag-fura-2).

c

n.d., binding not detected, or KZni≤109 M−1 (a lower limit for quin-2).