chemical state of trimethyl lead in the crystal

From: Edward A. Berry
Date: 20 January 2012 23:59


Does trimethyl lead tend to lose the Me in aqueous buffers?

A colleague is preparing to deposit a 2.9A structure that
was refined against the TML derivative (higher resolution than native).
Since the Pb was added as trimethyllead, the first inclination is
to report the heavy atoms as TML, ligand ID PBM.

However there is no density for the Me's, not surprising at this
resolution and because they are probably rotationally disordered.
So she doesn't know where to put them, and if they are omitted
they will add to the missing atoms list in her PDB file.

Also the Pb tend to be around Arg and Lys, whereas TML is
apparently a cation (TML-Acetate?). So I wonder if the compound
hydrolyzes to some kind of possibly anionic Pb(OH)n

Also, if it is TML what should the Pb-C bond lengths be?
Parameter file from HicUp (based on PDB) has ~2.2, but
phenix.elbow puts it at 2.5 A.

eab