Hi Bernhard,
the interaction you are referring to is usually referred to as CH-pi
interaction and not 'stacking', and that notation implies, as was
pointed out, that the hydrophobic face of pyranose rings (most often
GAL) is positioned such that the CH bond vectors interact with the
aromatic orbitals. This interaction is a signature of lectin-glycan
complexes - aromatic residues, especially tryptophan residues, are
massively enriched in lectin binding sites. Despite the name the major
energy gain of the apparant 'stacking' is, however, due to vdw
interactions, with only about 0.5 kcal/mole contribution form the
CH-pi interaction.
Regards from the ACS meeting Carb session :)
Bärbel
Zitat von Bernhard Rupp <[email protected]>:
Thanks to all the respondents. Very useful links on a generally interesting
topic. I was pretty sure
that this is another case of imprecise notation/definition because even with
my limited QM I cannot see a
true pi-stacking in the sense of the narrow definition.
But, it seems to be frequently used in the context with sugarCH-aromatic
interaction, which is not good.
Much obliged, BR
_____
From: CCP4 bulletin board [[email protected]] on behalf of Bernhard Rupp
[[email protected]]
Sent: Wednesday, August 23, 2017 8:18 PM
To: [email protected] <mailto:[email protected]>
Subject: [ccp4bb] Sugar-Pi-stacking
Hi Fellows,
there are some smart chemists amongst you, so I wonder - what precisely am I
to understand is
the nature of pi-stacking between an aromatic residue or (whatever
pi-orbital moiety) and a sugar moiety, disaccharide etc.?
Thanks for your help,
BR
------------------------------------------------------
Bernhard Rupp
http://www.hofkristallamt.org/
[email protected] <mailto:[email protected]>
+1 925 209 7429
+43 767 571 0536
------------------------------------------------------
All models are wrong
but some are useful.
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--
Bärbel Blaum, Ph.D.
Interfakultäres Institut für Biochemie (IFIB)
Hoppe-Seyler-Strasse 4
D-72076 Tübingen
Germany
+49 70 71 29 75 359
