Characterisation by immobilised metal ion affinity chromatographic procedures of the binding behaviour of several synthetic peptides designed to have high affinity for Cu(II) ions.
In this investigation, several peptides containing an increasing number of histidine residues have been designed and synthesised. The peptides involved repeat units of either the pentameric EAEHA or the tetrameric HLLH sequence motifs. Adsorption isotherms for these synthetic peptides and hexahistidine (hexa-His) as a control substance were measured under batch equilibrium binding conditions with an immobilised Cu(II)-iminodiacetic acid (IDA) sorbent. The experimental data were analysed in terms of Langmuirean binding behaviour. In common with previous studies with synthetic peptides, these investigations have demonstrate that the sequential organisation of the histidine side chains in these peptides can affect the selectivity of the coordination interactions with borderline metal ions in immobilised metal ion affinity chromatographic systems. The results also confirm that peptides selected on the basis of their potential to form amphipathic secondary structures with their histidine residues presented on one face of the molecule can exhibit equivalent or higher affinity constants towards copper ions than hexa-His, although they contain fewer histidine residues. These findings are thus relevant to the selection of peptides produced inter alia by combinatorial synthetic procedures to have enhanced binding properties for Cu(II) or Ni(II) ions, or intended for use as peptide tags in the fusion handle approach for the affinity chromatographic purification of recombinant proteins.
Kronina
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VV
Centre for Bioprocess Technology, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
Wirth
H J
HJ
Hearn
M T
MT
D000595:Amino Acid Sequence; D002846:Chromatography, Affinity / Q000379:methods*; D003300:Copper / Q000378:metabolism*; D013058:Mass Spectrometry; D008670:Metals; D010455:Peptides / Q000378:metabolism*; D011485:Protein Binding
D008670:Metals; D010455:Peptides; D003300:Copper