Insights into the structure-function relationship of the NorQ/NorD chaperones from Paracoccus denitrificans reveal shared principles of interacting MoxR AAA+/VWA domain proteins

Table 1 ATPase activity of purified NorQ and NorQD complex constructs

Protein construct	Malachite green assay (nmol mg⁻¹ min⁻¹)	NADH-coupled assay (nmol mg⁻¹ min⁻¹)	NADH-coupled assay (min⁻¹/complex)
NorQ	74 ± 2 (100%) (n=2)	141±8 (100%) (n=3)	25 ± 1 (100%) (n=3)
NorQ^WB	1.6 ± 0.2 (3%) (n=2)	1.5 ± 0.2 (1%) (n=3)	0.30 ± 0.04 (1%) (n=3)
NorQD	9 ± 1 (13%) (n=2)	30 ± 0.8 (21%) (n=3)	7.4 ± 0.2 (30%) (n=3)
NorQ^WBD	7 ±1 (10%) (n=2)	12.8 ± 0.3 (9%) (n=3)	3.2 ± 0.1 (13%) (n=3)
dt-NorQD	4 ± 1 (5%) (n=2)	3 ± 2 (2%) (n=2)	0.7 ± 0.5 (3%) (n=2)
dt-NorQ^WBD	1.3 ± 0.3 (2%) (n=2)	0.9 ± 0.4 (1%) (n=3)	0.2 ± 0.1 (1%) (n=3)

Experimental conditions: NADH-coupled assay: 50 mM TRIS/HCl, pH 8.0, 150 mM NaCl, 15 mM MgCl₂, 2.5 mM ATP, 1 mM phosphoenolpyruvate, 0.3 mM NADH, 12 U/mL pyruvate kinase, 12 U/mL lactate dehydrogenase. Malachite green assay: 50 mM TRIS/HCl, pH 8, 150 mM NaCl, 10% (v/v) glycerol, 20 mM MgCl₂, 2 mM ATP. dt double-tagged construct. Data (see Additional file 4) presented as averages with standard error

ISSN: 1741-7007