This is the subunit with retinal (shown in red). Long stretched helices.
Retinal is bonded to a lysine residue (pink) to form an iminium ion. Or protonated Schiff base as they say if they are trying to confuse me. Retinal fits nicely into the helices. The π-system is almost planar only the double bond in the ring kind of sticks out. The 11-cis-bond (where I don't understand why it is called 11, probably a terpene nomenclature) is behind the green arc.
Carboxylic groups surrounding retinal are important for the charge distribution. You can select them in PyMOL with the following command (after making a selection "retinal" with retinal):
select SurrAc, (retinal around 10) and resn asp+glu
There is one at the iminium group ...
... and one at the β-ionone ring.
They give the molecule kind of a jungle feeling.