Figure 1. NdhV gene deletion and its effect on NDH-1 activity.

(A) Construction of plasmid to generate NdhV deleted mutant (ΔndhV). Schematic representation of the ΔndhV mutant locus. A kanamycin resistance cassette about 1.2Kb was inserted into the NdhV gene. (B) PCR segregation analysis of the ΔndhV mutant using the ndhV-up-F and ndhV-Dn-R primers (Table S1). (C) Monitoring of NDH-1 activity using chlorophyll fluorescence analysis. The top curve shows a typical trace of chlorophyll fluorescence in the WT of Synechocystis 6803. The cells (OD₇₃₀ around 0.4) supplemented with 10 mM NaHCO₃ were used for the measurement. After the sample was exposed to the actinic light (AL, 100 μmol photons m⁻² s⁻¹) for 90 s, AL was turned off, and the transient increase in chlorophyll fluorescence level was recorded, which was used to ascribe NDH-1 activity. The inset shows magnified traces from the box area.