logarithmic scale
color palette
violet_red
blues
greens
greys
purples
pinks
magma
viridis
yellow_green
spectral
purple_orange
red_blue
red_yellow_blue
pink_yellow_green
ARG
ASP
ASN
GLN
GLU
HIS
ILE
LEU
LYS
MET
PHE
PRO
TRP
TYR
SER
VAL
THR
CYS
chi-1
chi-2
chi-3
chi-4
chi-1
chi-2
chi-3
chi-4