Dear Gerwald, dear Artem,
As, in the absence of quantum mechanical calculations, we can only
speculate about the contribution of mesomeric states it seems to me
from the data presented that the left formula (i.e. without the
mesomeric effect) may match the structural situation, in particular
Hi,
Not sure what you mean by 'other way around' - the formula you drew is
what I was thinking about :) Mesomeric states in normal amidines are
averaged and should result in planarity - since this case does not seem to
have a planar geometry, there's a chance that the amidine never formed and
the
Thank you. I was thinking along the lines of amination but was
concerned about the reactivity of the His nitrogen...
To add more information about the system: this is an untagged
thermophile protein, no His column used for purification. It was heated
to 65 degC during purification at pH 6.8 a
Dear Colleagues,
The amidine originating from the condensation reaction between the
Met N-formyl group and the His side chain should be the other way
around! This would also be roughly consistent with the reported
geometry. In fact, there should be two mesomeric states, provided
there is N pr
Dear Colleagues,
The amidine originating from the condensation reaction between the
Met N-formyl group and the His side chain should be the other way
around! This would also be roughly consistent with the reported
geometry.
I hope you can see the formula:
Arne Skerra
At 5:56 Uhr -0400
If you're 100% sure that this is only one atom then amination comes to mind.
I have no clue what conditions would favor such reactivity but it is
possible that the formyl group on the Met was aminated with the cyclic N of
the histidine, resulting in either a substituted bis-amine (requires
reductio
