The AMBER95 Force Field

The AMBER95 Force Field has been manually installed in InsightII v95.0. This was accomplished by typing in the parameters listed in Cornell, et al., A Second Generation Force Field for the Simulation of Proteins, Nucleic Acids, and Organic Molecules, J. Am. Chem. Soc., Vol 117, pp 5179-5197, 1995, also listed at The Cornell et al. 1995 AMBER force field web site.

This implementation has the following caveats:


AMBER95 Forcefield Atom List

Atom Description
C sp2 carbonyl all-atom carbon and aromatic carbon with hydroxyl substituient in tyrosine
C* sp2 aromatic all-atom carbon in 5-membered ring with 1 substituent
CA sp2 aromatic all-atom carbon in 6-membered ring with 1 substituent
CB sp2 aromatic all-atom carbon in junction between 5- and 6-membered rings
CC sp2 aromatic all-atom carbon in 5-membered ring with 1 substituent and next to a nitrogen
CK sp2 aromatic carbon in 5-membered ring between 2 nitrogens and with 1 hydrogen
CM sp2 all-atom carbon in pyrimidine at positions 5 or 6
CN sp2 aromatic junction all-atom carbon in between 5- and 6-membered rings
CQ sp2 all-atom carbon in 6-membered ring of purine between two NC nitrogens and with 1 hydrogen
CR sp2 aromatic all-atom carbon in 5-membered ring between 2 nitrogens and with 1 hydrogen (in HIS)
CT sp3 all-atom carbon with 4 explicit substituents
CV sp2 aromatic all-atom carbon in 5-membered ring bonded to 1 N and 1 H
CW sp2 aromatic all-atom carbon in 5-membered ring bonded to N-H and 1 H
H amide or imino hydrogen
H1 H aliph. bond. to C with 1 electrwd. group
H2 amino hydrogen in NH2
H3 hydrogen of lysine or arginine (positively charged)
HC explicit hydrogen attached to carbon
HA amino hydrogen in NH2
H4 H arom. bond. to C with 1 electrwd. group
H5 H arom. bond. to C with 2 electrwd. groups
HP H bonded to C next to positively charged gr
HO hydrogen in hydroxyl group
HS hydrogen attached to sulfur
HW hydrogen in water
LP lone pair
N sp2 nitrogen in amide
N* sp2 nitrogen in purine or pyrimidine wiht alkyl group
N2 sp2 nitrogen in base NH2 group or arginine NH2
N3 sp3 nitrogen with 4 substituents
NA sp2 nitrogen in 5-membered ring with hydrogen attached
NB sp2 nitrogen in 5-membered ring with lone pairs
NC sp2 nitrogen in 6-membered ring with lone pairs
O carbonyl oxygen
O2 carboxyl or phosphate non-bonded oxygen
OH alcohol oxygen
OS ether or ester oxygen
OW water oxygen
F fluorine
P phosphorus in phosphate group
S sulfur in disulfide linkage or methionine
SH sulfur in thiol
C0 calcium ion (+2)
IM chlorine ion (-1)
I Iodine ion (-1)
IP sodium ion (+1)
IB 'big ion w/ waters' for vacuum (Na+, 6H2O)
QC cesium ion (+1)
QK potassium ion (+1)
QL lithium ion (+1)
QN sodium ion (+1)
QR rubidium ion (+1)
CS sp3 carbon
h$ atom for automatic parameter assignment
c$ atom for automatic parameter assignment
n$ atom for automatic parameter assignment
o$ atom for automatic parameter assignment
s$ atom for automatic parameter assignment
p$ atom for automatic parameter assignment
ospc oxygen in SPC water molecule - used for rattle routine
otip oxygen in TIP3P water molecule - used for rattle routine
hspc hydrogen in SPC water molecule - used for rattle routine
htip hydrogen in TIP3P water molecule - used for rattle routine

all-atom carbon = this atom only includes the carbon---hydrogens must be explicitly defined
united carbon = this atom includes the carbon AND the hydrogen---hydrogens are incorporated into the definion of the heavy atoms


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Last updated: 01/23/2001