Role of Type 2 NAD(P)H Dehydrogenase NdbC in Redox Regulation of Carbon Allocation in Synechocystis

Abstract

H dehydrogenases comprise type 1 (NDH-1) and type 2 (NDH-2s) enzymes. Even though the NDH-1 complex is a wellcharacterized protein complex in the thylakoid membrane of Synechocystis sp. PCC 6803 (hereafter Synechocystis), the exact roles of different NDH-2s remain poorly understood. To elucidate this question, we studied the function of NdbC, one of the three NDH-2s in Synechocystis, by constructing a deletion mutant (DndbC) for a corresponding protein and submitting the mutant to physiological and biochemical characterization as well as to comprehensive proteomics analysis. We demonstrate that the deletion of NdbC, localized to the plasma membrane, affects several metabolic pathways in Synechocystis in autotrophic growth conditions without prominent effects on photosynthesis. Foremost, the deletion of NdbC leads, directly or indirectly, to compromised sugar catabolism, to glycogen accumulation, and to distorted cell division. Deficiencies in several sugar catabolic routes were supported by severe retardation of growth of the DndbC mutant under light-activated heterotrophic growth conditions but not under mixotrophy. Thus, NdbC has a significant function in regulating carbon allocation between storage and the biosynthesis pathways. In addition, the deletion of NdbC increases the amount of cyclic electron transfer, possibly via the NDH-1 2 complex, and decreases the expression of several transporters in ambient CO 2 growth conditions.

Global proteome response ofSynechocystis6803 to extreme copper environments applied to control the activity of the induciblepetJpromoter

“…; Huokko et al . ). Relative H/S quantification demonstrated proteome modifications which occurred at the phase of biomass accumulation and were caused by increased Cu 2+ concentration.…”

“…; Huokko et al . ). Proteins were identified with at least two unique peptides; few proteins identified based on one peptide were included, too, after manual examination.…”

“…For the validation of spectra identifications, Percolator algorithm was used with relaxed false discovery rate of 0Á05. Three biological replicates were assessed for each growth condition, and protein abundances were estimated based on area of the peaks representing corresponding peptides (Grouneva et al 2016;Huokko et al 2017). Proteins were identified with at least two unique peptides; few proteins identified based on one peptide were included, too, after manual examination.…”

“…Protein preparations from cells collected in S, H and D stages ( Fig. 1) were analysed in parallel using the label-free LC-MS/MS proteomic approach (Bantscheff et al 2007;Grouneva et al 2016;Huokko et al 2017). Relative H/S quantification demonstrated proteome modifications which occurred at the phase of biomass accumulation and were caused by increased Cu 2+ concentration.…”

Chlorosis as a Developmental Program in Cyanobacteria: The Proteomic Fundament for Survival and Awakening

“…Instead, they might function as by guest on June 7, 2019 http://www.mcponline.org/ Downloaded from cyanobacterial redox sensors and are potentially involved in redox-state regulation of the plastoquinone pool (51). Interestingly, deletion of the gene encoding a homologous type 2 NAD(P)H dehydrogenase leads to strongly compromised autotrophic growth, with impaired sugar catabolism and elevated glycogen accumulation; during heterotrophic growth, its deletion severely retards growth (52). Elevated levels of Slr0851 might be part of the machinery prepared during chlorosis for efficient sugar catabolism when resuscitation starts.…”