NMR Spectroscopic and Theoretical Analysis of a Spontaneously Formed Lys–Asp Isopeptide Bond

One bond makes all the difference: Three suitably positioned amino acid side chains (see picture) and a hydrophobic environment are all that is required for an amidation reaction with remarkable consequences. An emerging central building block of bacterial surface proteins owes its stability to a spontaneously formed isopeptide bond. The impact of this bond on protein structure and dynamics and the mechanism of its formation are scrutinized in detail. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.