N&PD Moderators: Skorpio | someguyontheinternet
I have the same feeling with lots of threads here at ADD.I have a constant feeling people do not read the whole thread before posting.
To answer this, I quote a post from Erny (from the dark side of the force):Is Phe339 involved in π-π interactions with the planar aryl component of ergolines, tryptamines and phenethylamines? Without the phenyl ring all these lose activity.
There are no aromatic amino acids for п-stacking in Nichols model as well, although it is evident from mutagenesis studies, that there should be some interaction between Phe 340 (222) and phenylethylamine molecules that is vial for their activity.
It certainly does, it depends on the type of hydrogen bond that is possible with the appropriate amino acid residue, possible orientations of electron pairs in the substituent and residue atoms, steric hindrance and such. Wer'e talking about 5-HT2A receptor topology.IGNVS said:so basically what im getting from that is that it dosnt matter whats stuck on there (carbonyl or methoxy, hydroxy etc...) right?
Michael Robert Braden said:The trends observed in these figures seem to indicate that both F6.51(339) and F6.52(340) are interacting with the N-Benzyls, whereas F6.52(340) appears to be interacting mainly with N-unsubstituted phenethylamines and the other classic agonists. The ∆∆G° values of about 2-4 kcal/mol and centroid-centroid distances of about 4.6 to 4.9Å are consistent with the energy and orientation of a “T-shape” π-π interaction (Jorgensen and Severance, 1990).
...
These results seem to indicate that an interaction of N6.55(343) with ergolines or N-Benzyls does not occur, or is not critical for binding and/or activity. There seems to be some indication that ring-substituted tryptamines may be able to adopt an orientation alternate to the conventional view in the agonist binding site so they can interact with N6.55(343). One could imagine the indole ring “flipping over” so that the indole nitrogen hydrogen would interact with the carbonyl oxygen of N6.55(343). Similarly, mescaline and its analogues may be adopting alternate or additional orientations that allow them to interact with this residue. Therefore, additional experiments with N(1)- substituted tryptamines at this mutant receptor may be necessary. Alternately, it is possible that N6.55(343) is an anchoring residue for the extracellular loop connecting TM4 and TM5 (EL2). The “capping” of the receptor by EL2 may alter ligand signaling or bring other receptor residues into contact with the ligand and could be altered by the N6.55(343)A mutant. This possibility is very difficult to model due to lack of accurate solvation of these residues in our work.
Can I get more information (citation?) for that Ralf Heim dissertation?
Here it is.
_http://www.diss.fu-berlin.de/diss/receive/FUDISS_thesis_000000001221