In support of curiosity-driven research
Oeiras, 21.01.2015
Researchers from the Cell Physiology & NMR Lab at ITQB have discovered a novel pathway for the synthesis of inositol phospholipids, important components of cell membranes. The whole project is yet another example of how extensive biochemical knowledge needs to be gathered before assigning functions to the many genes whose function is unknown. The work is published in Environmental Microbiology (IF = 6.2).
The Cell Physiology & NMR group has a long history of work on the biosynthetic pathways of compatible solutes in hyperthermophilic organisms. In particular, they identified the genes and enzymes involved in the synthesis of di-myo-inositol phosphate (DIP), a canonical solute of organisms adapted to thrive in very hot habitats. This is why they were puzzled by the presence in Rhodothermus marinus of a gene for the synthesis of CDP-inositol, a precursor of DIP synthesis, when this compound is absent from the solute pool of the bacterium. In a curiosity-driven research project, the team questioned the fate of CDP-inositol in R. marinus. They found that CDP-inositol was used to produce ether-linked inositol phospholipids, through a novel biosynthetic pathway, which involves activation of the polar head (inositol) instead of the lipid moiety, which is what happens in known pathways. Interestingly, the occurrence of ether-linked inositol phospholipids, typical of the domain Archaea, is rare within the domain Bacteria and had never been demonstrated before in Rhodothermus marinus.
The pathway involves a new synthase (BEPIS), a membrane protein which is also predictably present in the genome of a few pathogenic bacteria.
Helena Santos, who coordinated the study, believes that “truly innovative results often appear from curiosity-driven research projects, like this one, which spring from a simple question”.
Original Article
Environmental Microbiology doi: 10.1111/1462-2920.12734
A novel pathway for the synthesis of inositol phospholipids uses CDP-inositol as donor of the polar head group
Carla D. Jorge, Nuno Borges and Helena Santos
