Project description:Prochlorococcus marinus MIT 9303 is a marine cyanobacterium found in sea waters. It was first isolated from a depth of 100 m in the Sargasso Sea in the year 1992. This cyanobacterium serves as a good model system for scientific research due to the presence of many desirable characteristics like smaller in size, ability to perform photosynthesis and the ease of culture maintenance. The genome of this cyanobacterium encodes for about 3022 proteins. Out of these 3022 proteins, few proteins were annotated as hypothetical proteins. We performed a computational study to characterize one of the hypothetical proteins "P9303_05031" to deduce its functional role in the cell using various bioinformatics techniques. After in-depth analysis, this hypothetical protein showed the conserved domain as of Hsp10 of molecular chaperonins of GroES. In this work, we have predicted the bidirectional best hits for the hypothetical protein P9303_05031 followed by the prediction of protein properties such as primary, secondary and tertiary structures. The existence of the Hsp10 domain indicates its role is essential for the folding of proteins during heat shock. This work represents the first structural and physicochemical study of the hypothetical protein P9303_05031 in Prochlorococcus marinus MIT 9303.
Project description:Prochlorococcus marinus is a highly abundant picocyanobacterium in Earth’s oceans and therefore a significant contributor to global primary production. This organism exists as different ecotypes, each occupying particular environments in the euphotic zone that differ in both solar penetration and nutrient levels. The ecotypes analysed here were isolated from depths of 5 m (MED4), 135 m (MIT9313) and 120 m (SS120) and cultured at low illumination. MED4, adapted to high light levels closer to the surface, was compared at both low and high illumination. In contrast to other cyanobacteria such as Synechocystis with a dominance of photosystem I (PSI) over photosystem II (PSII) complexes in the thylakoid membranes, MED4 and MIT9313 showed about equal levels. In MED4, the relative levels were almost the same in both the high and low light cultures. SS120 thylakoids contained a lower cytochrome b6f content and around two-fold more PSII than PSI. Additionally a significantly higher abundance of light-harvesting Pcb proteins was found in SS120 than the other ecotypes. This proteomic comparison was employed in conjunction with thylakoid membrane AFM imaging to rationalize the strategies these ecotypes use to survive in the different oceanic environments.
