Table 2 Affinity of Zur proteins for DNA and Zn2+

The DNA-binding affinities refer to fully metallated Zur, except for mutant proteins.

OrganismKD (DNA)KD (Zn)
Bacillus subtilis4.3 nM (FA [40])
6 nM (EMSA [41])
WT: 12.5–25.4 nM, site 2 mutant: 16.5nM for PrpsNB;* 80.6 nM for PyciC; site 3 mutant: ∼100 nM (EMSA [12])
KD1 = 5.5 × 10−14 M (0.9 Zn/monomer)
KD2 = 1.2 × 10−12 M (0.5 Zn/monomer)
(titration against Quin-2 [40])
KD1 = 4.2 × 10−15 M (0.1 μM BsZur)
= 5.9 × 10−16 M (1.0 μM BsZur)
(In vitro Zn2+ activation assay [40])
Streptomyces coelicolor17.7 nM PrpmG2; 17.6 nM PSCO7682; 74.9 nM PznuA; 68.3 nM PrpmF2 (EMSA [38])
15 nM PznuA1, 19 nM PznuA2 and PzitB (EMSA [55])
7.8–4.5 × 10−16 M (EMSA, Zn titration in the presence of TPEN [38])
E. coli8.2 ± 0.7 × 10−18 M2 (PznuC)
0.053 ± 0.01 × 10−18 M2 (PzinT)
0.025 ± 0.01 × 10−18 M2 (Pl31p)
520 ± 90 × 10−18 M2 (PpliG)
(Zur2Zn4)2-Pxxxx; EMSA [17]
9.6 ± 3.0 × 10−17 M (in vitro DNA binding)
2.0 ± 0.1 × 10−16 M (transcription assay PznuC [4])
Salmonella entericaZur2Zn6: 54 ± 18 nM
Zur2Zn4: 41 ± 10 nM
Zur2Zn2: ≥2.7 ± 0.4 × 10−5 M
(FA [45])
K1–2 6.36 ± 0.41 × 10−13 M (titration against Quin-2)
K3 8.04 ± 2.92 × 10−11 M (titration against Quin-2)
K4 ≥5 × 10−7 M (titration against MagFura2)
Indices refer to binding sites on dimer, with structural sites already occupied [44]
Anabaena sp. PCC 7120220 ± 10 nM (EMSA [48])
Pall4725: 2.5 nM
Pall4723: 7 nM (EMSA [60])
Isothermal titration calorimetry (ITC): [48]
ZurZn + Zn ↔ ZurZn2, KD ∼3.5 × 10−7 M
ITC in the presence of DTT: two sites; KD1 = 6.5 × 10−7 M
Synechocystis sp. PCC 6803KD ≤ 55 nM (FA [47,61])KD1 = 2.3 ± 1.9 × 10−13 M (titration against Quin-2 [47,61])
Paracoccus denitrificansn.d.KD1 = 4.0 ± 0.4 × 10−8 M (titration against MagFura2)
KD2 > 1×10−6 M [46]
  • * Pxxxx: Promoter for gene xxxx. Quin-2: 2-[(2-amino-5-methylphenoxy)methyl]-6-methoxy-8-aminoquinoline-N,N,N′,N′-tetraacetic acid. MagFura2: 2-[6-[bis(carboxymethyl)amino]-5-(carboxymethoxy)-2-benzofuranyl]-5-oxazolecarboxylic acid.