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Specialty Chemistry Forums => Biochemistry and Chemical Biology Forum => Topic started by: psudhakar79 on September 10, 2012, 07:01:04 PM

Title: Cu+ and Zn2+ coordination
Post by: psudhakar79 on September 10, 2012, 07:01:04 PM

Hello All,

I'm studying Cu+ and Zn2+ coordination to a Histidine containing peptide. I'm wondering what is the major difference between the two metal ions apart from mono valent and divalent cations. Is there any particular similarity between them apart from the electronic configuration.

Does it bind to the peptide in the same fashion or differently. Can we treat the two metal ions in the same way for NMR chemical shift calculations.

Any kind of help is appreciated

Thank you
Regards
Parth

Title: Re: Cu+ and Zn2+ coordination
Post by: Babcock_Hall on September 11, 2012, 10:18:39 AM

Zinc coordination brings about a surprisingly large chemical shift change on the nitrogen N-15 signal.  I don't recall what copper might do.

Title: Re: Cu+ and Zn2+ coordination
Post by: vex on September 13, 2012, 11:43:24 AM

Cu⁺ and Zn²⁺ are isoelectronic. Cu⁺ will not be magnetically active or Jahn-Teller active (as Cu²⁺ is), so the coordination geometry should be roughly the same as for the zinc coordination, and nitrogen NMR should not be significantly affected (between Cu and Zn). The only thing I would expect to see change is the equilibrium bond length between the histidine N and the metal cation, with a shorter bond length for the divalent cation, based solely on electrostatics.

Maybe I'm oversimplifying, but it doesn't seem that there should be a huge difference. Just remember that Cu⁺ is very easily oxidized.