tRNA-dependent addition of amino acids to cell wall and membrane components.

The objective of the present review is to provide an insight into modifications of microbial cell walls and membrane constituents by using the aminoacyl-tRNA as amino acid donor. In bacteria, phospholipids are modified by Multiple peptide resistance Factor enzymes and peptidoglycan precursors by so called fem ligases. Although these modifications were thought to be restricted to procaryotes, we discovered enzymes that modify ergosterol (the main component of fungal membrane) with glycine and aspartate. The focus of this review is to present the molecular mechanisms underlying all these processes together with the structure of the enzymes and their substrates. This article also reviews how substrates are recognized and modified and how the products are subsequently exported in various organisms. Finally, the physiological outcome and the discoveries of each family of enzymes is also discussed.