AbstractsBiology & Animal Science

Regulation of the Pho Regulon and Reconstruction of the Photosynthetic Apparatus under Phosphate Limitation in Synechocystis sp. PCC 6803

by Jacob Ryan Irby

Institution: University of Otago
Department: Biochemistry
Degree: Master's Degree
Year: 2021
Keywords: Cyanobacteria; Synechocystis sp. PCC 6803; Synechocystis; Phosphate; Limitation; Pho; Regulon; Periplasmic; SphX; Pst 1; PstS1; Luxury; Uptake; sll0540; SphZ; Auxiliary; Sensor; SphS; SphR; Signal Transduction; SphU; Negative Regulator; Pst 2; PstS2; Photosynthesis; Photosynthetic; Apparatus; Low-Temperature; 77K; Fluorescence; Emission; Spectroscopy; Parameterized; Parametric; Phycobilisome; PS II; CP43; CP47; PS I; Cyclic; Electron; Transport; Iron; isiA; CP43'; New Zealand; Pst1; Pst2
Posted: 08/12/2021
Record ID: 2222252
Full text PDF: https://ourarchive.otago.ac.nz/handle/10523/12191


For millennia, cyanobacteria have evolved strategies for acclimatization to dynamic environments – this requires a molecular response system. Phosphate is essential for cellular integrity and metabolism, yet inorganic phosphate is often the limiting nutrient for most aquatic environments. This study characterizes two periplasmic phosphate-binding proteins, namely SphX and SphZ, which are essential for the functional response of the SphS-SphR signal transduction system in Synechocystis sp. PCC 6803 and incorporates both into a model. SphX offers a competitive role so as to ensure inorganic phosphate is not depleted from the environment at a faster rate than is necessary for metabolism and, therefore, hinders luxury uptake; whereas, SphZ, encoded by sll0540, is the auxiliary sensor necessary for the SphS response under phosphate limitation in tandem with a protein complex association with the phosphate-specific transport 2 system and the negative regulator, SphU. Cross-regulation between the pho regulon and the photosynthetic apparatus is presented as well as a parameterized analysis for low-temperature fluorescence emission spectroscopy.