From 6a0b7bedde11a56d6aa94519e37f3da9ba454608 Mon Sep 17 00:00:00 2001
From: acballesteros 8.1. Build CG representationsCaution
The mapping to CG requires the correct protonation state of each residue at a given pH. We recommend using the CHARMM-GUI server with the Glycan Reader & Modeler to prepare your system, choosing the output naming scheme of AMBER for best compatibility. An account is required to access any of the CHARMM-GUI Input Generator modules, and it can take up to 24 hours to obtain one.
-This example use the structure of glycoprotein 1GYA, using CHARMM-GUI server are obtained the files parm7 and rst7, this files are converted to pdb format with naming scheme of AMBER/GLYCAM using AmberTool as follow:
+This example use the structure of glycoprotein 1GYA, using CHARMM-GUI server are obtained the files parm7 and rst7, these files are converted to pdb format with the naming scheme of AMBER/GLYCAM using AmberTool as follow:
ambpdb -p ./sirah.amber/tutorial/8/step3_input.parm7 -c ./sirah.amber/tutorial/8/step3_input.rst7 > 1GYA_glycam.pdb
From the file 1GYA_glycam.pdb generated delete the solvent, rename to 1GYA_glycam_NoW.pdb and then map the protonated atomistic to its CG representation:
+From the file 1GYA_glycam.pdb generated delete the solvent, rename to 1GYA_glycam_NoW.pdb and then map the protonated atomistic structure to its CG representation:
./sirah.amber/tools/CGCONV/cgconv.pl -i ./sirah.amber/tutorial/8/1GYA_glycam_NoW.pdb -o 1GYA_cg.pdb
Important
-By default charged termini are used, but it is possible to set them neutral by renaming the residues from s[code] to a[code] (Nt-acetylated) or m[code] (Ct-amidated) after mapping to CG, where [code] is the root residue name in SIRAH. For example, to set a neutral N-terminal Histidine protonated at epsilon nitrogen (\(N_{\epsilon}\)) rename it from “sHe” to “aHe”.
+By default, charged termini are used. However, it is possible to set them neutral by renaming the residues from s[code] to a[code] (Nt-acetylated) or m[code] (Ct-amidated) after mapping to CG, where [code] is the root residue name in SIRAH. For example, to set a neutral N-terminal Histidine protonated at epsilon nitrogen (\(N_{\epsilon}\)) rename it from “sHe” to “aHe”.
Please check both PDBs structures using VMD:
The folder sirah.amber/tutorial/8/
contains typical input files for energy minimization
-(em1_WT4.in
and em2_WT4.in
), equilibration (eq1_WT4.in
and eq2_WT4.in
) and production (md_WT4.in
) runs. Please check carefully the
+(em1_WT4.in
and em2_WT4.in
), relaxation (or equilibration) (eq1_WT4.in
and eq2_WT4.in
) and production (md_WT4.in
) runs. Please check carefully the
input flags therein, in particular the definition of flag chngmask=0 at &ewald section is mandatory.
Tip
@@ -246,7 +246,7 @@pmemd.cuda -O -i ../sirah.amber/tutorial/8/em2_WT4.in -p ../1GYA_cg.prmtop -c ../1GYA_cg_em1.ncrst -o 1GYA_cg_em2.out -r 1GYA_cg_em2.ncrst &
Solvent Equilibration (NPT):
+Solvent Relaxation (or equlibration) in NPT:
pmemd.cuda -O -i ../sirah.amber/tutorial/8/eq1_WT4.in -p ../1GYA_cg.prmtop -c 1GYA_cg_em2.ncrst -ref 1GYA_cg_em2.ncrst -o 1GYA_cg_eq1.out -r 1GYA_cg_eq1.ncrst -x 1GYA_cg_eq1.nc &
Option restraintmask=:’1-114’ in input file eq1_WT4.in
must be set specifically for each system to embrace all glycoprotein’s residues.
Soft equilibration to improve side chain and glycan solvation (NPT):
+Soft Relaxation to improve side chain and glycan solvation (NPT):
pmemd.cuda -O -i ../sirah.amber/tutorial/8/eq2_WT4.in -p ../1GYA_cg.prmtop -c 1GYA_cg_eq1.ncrst -ref 1GYA_cg_eq1.ncrst -o 1GYA_cg_eq2.out -r 1GYA_cg_eq2.ncrst -x 1GYA_cg_eq2.nc &
The mapping to CG requires the correct protonation state of each residue at a given pH. We recommend using the CHARMM-GUI server with the Glycan Reader & Modeler to prepare your system, choosing the output naming scheme of AMBER for best compatibility. An account is required to access any of the CHARMM-GUI Input Generator modules, and it can take up to 24 hours to obtain one.
-This example use the structure of glycoprotein 1GYA, using CHARMM-GUI server are obtained the files parm7 and rst7, this files are converted to pdb format with naming scheme of AMBER/GLYCAM using AmberTool as follow:
+This example use the structure of glycoprotein 1GYA, using CHARMM-GUI server are obtained the files parm7 and rst7, these files are converted to pdb format with the naming scheme of AMBER/GLYCAM using AmberTool as follow:
ambpdb -p ./sirah.amber/tutorial/8/step3_input.parm7 -c ./sirah.amber/tutorial/8/step3_input.rst7 > 1GYA_glycam.pdb
From the file 1GYA_glycam.pdb generated delete the solvent, rename to 1GYA_glycam_NoW.pdb and then map the protonated atomistic to its CG representation:
+From the file 1GYA_glycam.pdb generated delete the solvent, rename to 1GYA_glycam_NoW.pdb and then map the protonated atomistic structure to its CG representation:
./sirah.amber/tools/CGCONV/cgconv.pl -i ./sirah.amber/tutorial/8/1GYA_glycam_NoW.pdb -o 1GYA_cg.pdb
Important
-By default charged termini are used, but it is possible to set them neutral by renaming the residues from s[code] to a[code] (Nt-acetylated) or m[code] (Ct-amidated) after mapping to CG, where [code] is the root residue name in SIRAH. For example, to set a neutral N-terminal Histidine protonated at epsilon nitrogen (\(N_{\epsilon}\)) rename it from “sHe” to “aHe”.
+By default, charged termini are used. However, it is possible to set them neutral by renaming the residues from s[code] to a[code] (Nt-acetylated) or m[code] (Ct-amidated) after mapping to CG, where [code] is the root residue name in SIRAH. For example, to set a neutral N-terminal Histidine protonated at epsilon nitrogen (\(N_{\epsilon}\)) rename it from “sHe” to “aHe”.
Please check both PDBs structures using VMD:
vmd -m sirah.amber/tutorial/8/1GYA_glycam_NoW.pdb 1GYA_cg.pdb
@@ -1664,7 +1664,7 @@ 8.4. Run the simulationsirah.amber/tutorial/8/ contains typical input files for energy minimization
-(em1_WT4.in
and em2_WT4.in
), equilibration (eq1_WT4.in
and eq2_WT4.in
) and production (md_WT4.in
) runs. Please check carefully the
+(em1_WT4.in
and em2_WT4.in
), relaxation (or equilibration) (eq1_WT4.in
and eq2_WT4.in
) and production (md_WT4.in
) runs. Please check carefully the
input flags therein, in particular the definition of flag chngmask=0 at &ewald section is mandatory.
Tip
@@ -1697,7 +1697,7 @@ 8.4. Run the simulationpmemd.cuda -O -i ../sirah.amber/tutorial/8/em2_WT4.in -p ../1GYA_cg.prmtop -c ../1GYA_cg_em1.ncrst -o 1GYA_cg_em2.out -r 1GYA_cg_em2.ncrst &
-Solvent Equilibration (NPT):
+Solvent Relaxation (or equlibration) in NPT:
pmemd.cuda -O -i ../sirah.amber/tutorial/8/eq1_WT4.in -p ../1GYA_cg.prmtop -c 1GYA_cg_em2.ncrst -ref 1GYA_cg_em2.ncrst -o 1GYA_cg_eq1.out -r 1GYA_cg_eq1.ncrst -x 1GYA_cg_eq1.nc &
@@ -1705,7 +1705,7 @@ 8.4. Run the simulationCaution
Option restraintmask=:’1-114’ in input file eq1_WT4.in
must be set specifically for each system to embrace all glycoprotein’s residues.
Soft equilibration to improve side chain and glycan solvation (NPT):
+Soft Relaxation to improve side chain and glycan solvation (NPT):
pmemd.cuda -O -i ../sirah.amber/tutorial/8/eq2_WT4.in -p ../1GYA_cg.prmtop -c 1GYA_cg_eq1.ncrst -ref 1GYA_cg_eq1.ncrst -o 1GYA_cg_eq2.out -r 1GYA_cg_eq2.ncrst -x 1GYA_cg_eq2.nc &