Zn binding to polyhistidine

Thu Aug 27 18:55:57 EST 1992

Does anyone know the relationship between the number of 
histidine residues and the binding affinity to Zn++?  
We are working with an enzyme with 3 identical subunits.  
We would like to make hybrid enzymes containing 1, 2, and 
3 mutant subunits, purify them, and analyze the kinetics.  
The present scheme is to add 3 His residues on the end of 
the wild type subunit by genetic engineering, expressing 
this in the presence of the gene coding for the mutant 
subunit, and purifing the hybrid molecules by Zn chelate 
affinity chromatography.  For this to work, all three of 
the hybrid molecules must differ significantly in their 
ability to bind to Zn++.  

Any suggestions?


David Mueller
Department of Biological Chemistry
The Chicago Medical School
North Chicago IL

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