Bacterial cell growth promotion and inhibition The cell wall of a bacterium is a very important structure for its survival and the target of many antibiotics such as penicillin. Future development of antimicrobials to counter resistance could depend on research into the molecular details of cell wall growth. Health © Shutterstock Gram-negative bacteria such as Escherichia coli have a cell wall or envelope composed of peptidoglycan (PG) that protects against a hostile and changing environment. During the cell cycle, two sometimes interacting protein complexes – elongasome and divisome – are active, especially during the intermediate stage between wall elongation and cell division processes. The EU-funded PGRECONST (Assembly and coordination of peptidoglycan synthesis complexes during bacterial growth and cell division) project looked at the fabrication of the new PG in vitro. Particular focus was directed at essential proteins involved in regulation of the synthesis protein complexes. Researchers discovered new interactions involving proteins from both elongasome and divisome. The proteins have been characterised structurally and genetically and results confirmed in vivo. Data on the new interactions supports the theory of functional redundancy of the main bifunctional synthases PBP1A and PBP1B. Overall, the results show how robust the PG synthesis process is due to functional redundancy of these two main enzymes. The major result of PGRECONST – that PBP1A interacts with two cell division proteins that enhance its synthetic activity – is the subject of a paper in preparation for publication. Identification of the proteins involved in cell growth and division could lead to molecular design of new antibiotics. Keywords Bacterial cell growth, cell wall, peptidoglycan, protein complexes, cell division, PGRECONST
