    N 
   CA 
    C 
    O 
   CB 
   SG 
   C1 
   C2 
   C3 
   C4 
   C5 
   C6 
   C7 
   C8 
   C9 
  C10 
  C11 
  C12 
  C13 
  C14 
  C15 
  C16 
  C17 
  C18 
  C19 
  C20 
