*Changes for version 2.5 (9/9/21):
-Added divalent calcium cation (type HH) -Added monovalent sodium cation (type POS) -Added chloride anion as NEG site type (see solv.itp) -Added mkions function (v.1) -Tested with Gromacs v.2018
*Changes for version 2.4 (7/8/17): [PeerJ 6:e4230 (2018)]
-Assigned the following site types to match bilayer permeation profiles: Calpha backbone: POL Ala: APOL Asn: POL Lys: POL-POS Asp: POL-NEG Glu: POL-NEG Phe: APOL-APOL-POL Val: APOL-APOL Trp: APOL-POL-APOL-APOL
*Changes for version 2.3 (8/23/16): [AIMS Mol. Sci. 4:352 (2017)]
-Supports peptides of fewer than 4 residues (not capped).
-N/C-termini assigned as POS/NEG sites instead of Calpha site type.
-New site assignments based on PMF in DOPC bilayer [Biophys. J. 94:3393]: -Asn/Gln assigned two polar sites; Cys sidechain assigned as apolar -Trp/Tyr assigned two polar sites (Cgamma and Cepsilon) -Arg assigned two polar sites (Cbeta and Cgamma) and positive Cdelta -Lys assigned two polar sites (Cbeta and new midpoint particle)
-Added offset variable for membrane ndx/tcl files so protein atoms not numbered from 1.
*Changes for version 2.1: [Methods Mol. Biol. 1084:123 (2014)]
-Relaxed stiff bonds > 100 000 kJ mol-1 nm-2 to allow 5fs timestep.
*Changes for version 2.0:
-Includes Cbeta L chirality corrections [MiMB 1084:123]
-Excludes 1,4 nonbonded interactions for which a backbone dihedral exists.
-Removed tabulated bonds.