Difference in Conformation of Virginiamycin M1 in Chloroform and Bound Form in the 50S Ribosome or Streptogramin Acetyltransferase

The conformation of virginiamycin M1 (VM1) in chloroform, determined by high-resolution NMR experiments, differs significantly from that of the X-ray crystal structure of VM1 bound to the 50S ribosome and to the active site of a streptogramin acetyltransferase enzyme. This implies that the binding process to these entities causes a major change in VM1 conformation.