摘要：Protein cyclization has been shown to increase the stability of molecule structure by reducing the number of possible conformation variations. Cyclization of an enzyme can significantly enlarge the spectrum of its application in specific conditions, including high temperature, presence of a chaotropic agent, and denaturing environment. In this study the cyclic form of Staphylococcus aureus sortase A enzyme (srtA) was obtained by introducing a peptide bond between amino acids at N- and C-termini. The catalytic activity of purified cyclic srtA was tested in vitro by protein-protein ligation reaction. In contrast to the linear srtA, the cyclic form of the enzyme was active in presence of chaotropic agent. This finding suggests the potential use of srtA enzyme in protein engineering techniques
关键词：cyclization; sortase A; Staphylococcus aureus; transpeptidation; trans-splicing. ; Abbreviations: eGFP. Green Fluorescence protein; GST; glutahione-S-transferase; NMR; nuclear magnetic resonance; srtA; sortase A
