I've been trying to locate the residues involved in ligand binding for either rhodopsin or D2 dopamine receptor-- is there any place that I can just find a list or something?? pubmed hasnt helped very much so far
That's not my specific interest but I've seen something interesting in the literature.
Try medline again with selected keywords like ligand binding domain or docking.
There are works on 3D modelling, particularly on rhodopsin, that can help you to start with specific aminoacids.Good luck.
The binding sites for dopamine receptors are contained in a binding crevice formed by the transmembrane helices 3, 5, 6 and 7. The energetically most important interaction is most likely a salt bridge between the charged amine of ligands and the carboxylated side chain of Asp114 in TM 3.
Click on D-114 in this snake-like view: http://www.gpcr.org/7tm/seq/diagrams_MuteXt/DRD2_HUMAN-rbdg.html
and you will get details of contacts between ligands and DRD2:http://www.gpcr.org/7tm/mutation/SameResidue_Xtext/DRD2_HUMAN_114_Xtext.html
The photochromophore of rhodopsin and the opsins, 11-cis-retinal, is unique among the endogenous ligands for GPCRs in that it is covalently attached to the receptor within a binding crevice formed by the TM helices
I have found these review very useful to understand the molecular mechanisms of GPCR activation:
Gether U, Endocrine Reviews 21 (1): 90-113, 2000http://edrv.endojournals.org/cgi/content/full/21/1/90
Ji T. H., J Biol Chem, Vol. 273, Issue 28, 17299-17302, 1998http://www.jbc.org/cgi/content/full/273/28/17299?ijkey=279ffa21087f26af10709af810485e07fae32c22&keytype2=tf_ipsecsha