Mechanisms of Copper Ion Mediated Huntington's Disease Progression
Figure 2
Interaction of N-171 huntingtin with copper (II) by IMAC involves histidine 82 and 98. A. N171-17Q huntingtin contains several potential copper (II) coordinating residues, two histidines (red) and four cysteines (blue). The vertical line represents the exon-1-2 boundary. Flag tag sequence (underlined) partially overlaps with huntingtin sequence (upper case). B. Purified N-171-17Q huntingtin fragment elutes from copper column at pH 4.5–3.5 consistent with interaction with histidine residue(s). Elution solutions were prepared in 20 mM citrate-buffer. C. Modification of histidine 82 and/or 98 to phenylalanine results in elution of protein in washes indicating that both histidines are necessary for interaction with copper (II). D. Huntingtin exon-1-17Q fragment is sufficient for copper (II) interaction.