Rational Design and Self-Assembly of Histidine-Rich Peptides on a Graphite Surface

Histidine-rich peptides (HRPs) have been investigatedto createfunctional biomolecules based on the nature of histidine, such asion binding and catalytic activity. The organization of these HRPson a solid surface can lead to surface functionalization with thewell-known properties of HRPs. However, immobilization of HRPs onthe surface has not been realized. Here, we design a series of octapeptideswith histidine repeat units, aiming to establish their self-assemblyon a graphite surface to produce a highly robust and active nanoscaffold.The new design has (XH)(4), and we incorporated various typesof hydrophobic amino acids at X in the sequence to facilitate theirinteraction with the surface. The effect of the pair of amino acidson their self-assembly was investigated by atomic force microscopy.Contact angle measurement revealed that these assemblies functionalizedgraphite surfaces with different wetting chemistry. Moreover, thesecondary structure of peptides was characterized by Fourier transforminfrared spectroscopy (FTIR), which gives us further insights intothe conformation of histidine repeat peptides on the surface. Ourresults showed a new approach to applying histidine-rich peptideson the surface and tuning the self-assembly behavior by introducingdifferent counter amino acids that could be integrated with a widerange of biosensing and biotechnology applications.