diff --git a/script/S112D.sh b/script/S112D.sh
index 9b03970..ea5fefa 100644
--- a/script/S112D.sh
+++ b/script/S112D.sh
@@ -8,6 +8,7 @@
 if [ -n "$GMXRC_PATH" ]; then
     source "$GMXRC_PATH" # source /home/lingyuzeng/software/gmx2023.2/bin/GMXRC
 fi
+GPU_ID=${GPU_ID:-"0"}
 NAME=${NAME:-"S112D-Alphafold2"}
 # FORCEFIELD=${FORCEFIELD:-"amber99sb-ildn"}
 FORCEFIELD=${FORCEFIELD:-"amber99sb"}
@@ -262,7 +263,7 @@ EOF
 gmx_mpi grompp -f ${MDRUN_NAME}.mdp -c npt.gro -t npt.cpt -p topol.top -o ${TPR_FILE}
 
 # Run the simulation
-gmx_mpi mdrun -deffnm ${MDRUN_NAME} -update gpu  -ntomp 1
+gmx_mpi mdrun -deffnm ${MDRUN_NAME} -update gpu  -ntomp 1 -gpu_id ${GPU_ID}
 
 # extra ndx file , select protein
 echo -e "1\nq" | gmx_mpi make_ndx -f ${MDRUN_NAME}.gro -o ${NDX_FILE}