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