md on peptide single copy
 &cntrl
  ntx=7, 
  ntf=2, ntc=2, ntpr=1, 
  nstlim=20, dt=0.001,
  ntb=2, ntp=1, temp0=300,
  taup = 0.2,
 /
 &ewald
  use_pme=0,eedmeth=4
 /

