Covering: up to May 2012 The β-lactam antibiotics and related β-lactamase inhibitors are amongst the most important small molecules in clinical use. Most, but not all, β-lactams including penicillins, cephalosporins, and clavulanic acid are produced via fermentation or via modification of fermented intermediates, with important exceptions being the carbapenems and aztreonam. The desire for more efficient routes to existing antibiotics and for access to new and synthetically challenging ones stimulates continued interest in β-lactam biosynthesis. We review knowledge of the pathways leading to β-lactam antibiotics focusing on the mechanisms, structures and biocatalytic applications of the enzymes involved.

Green chemistry has become a hot topic and the focus of not only many companies but also researchers.

Muraymycins are a promising class of antimicrobial natural products. These uridine-derived nucleoside-peptide antibiotics inhibit the bacterial membrane protein translocase I (MraY), a key enzyme in the intracellular part of peptidoglycan biosynthesis. This review describes the structures of naturally occurring muraymycins, their mode of action, synthetic access to muraymycins and their analogues, some structure–activity relationship (SAR) studies and first insights into muraymycin biosynthesis. It therefore provides an overview on the current state of research, as well as an outlook on possible future developments in this field.