A peptide that binds to the frayed collagen in wounds to anchor drug molecules to improve wound healing

A collagen-binding peptide with applications in wound healing has been developed by scientists in the US. The peptide is able to invade the strands of collagen, forming a strong and stable non-covalent bond at room temperature. Pendant drug molecules could be attached to the peptide and anchored at the wound site to aid wound healing.

Collagen is the most abundant protein in the body and makes up three quarters of the dry weight of skin. It is formed from three helical polypeptide strands containing the common amino acid motif proline-hydroxyproline-glycine. The collagen-binding peptide made by Ronald Raines at the University of Wisconsin-Madison and colleagues mimics a short section of a collagen strand, but the team substituted the proline and hydroxyprolines with fluoroproline. The fluoroproline-modified peptide binds strongly to collagen's triple helical structure, and the team found that it binds to animal collagen longer than non-modified peptides.     

Even though these peptides bind very strongly to collagen, they do not bind to each other. They exist as single strands looking for a partner. In a wound, single strands find the most partners in the areas where the collagen is most exposed and frayed. Although the peptides are simply following the laws of thermodynamics, elegantly, this is where they are needed most.

Raines' team is starting to apply their work to some practical problems in biomedicine, such as attaching dyes to the peptide for wound assessment. 'I really like this project because it extends truly from a quantum mechanical understanding of a complex biological molecule to a practical application that we think could help lots of people day to day,' says Raines.

'The use of annealing collagen mimetic peptides represents a significant advance over prior methods of collagen modification, which typically relied on covalent modification,' says Gregg Fields, an expert in synthetic protein design and construction at the Torrey Pines Institute for Molecular Studies, US. 'This creative approach is sufficiently flexible to allow for selective therapeutic intervention, which could greatly facilitate the healing process in a variety of difficult to treat wounds.'

In the future, Raines' team plans to use the collagen-binding peptide to anchor drug molecules to the frayed collagen at wound sites. The peptide may be useful for the treatment of painful wounds, such as burns, because it can decrease the number of repeat applications required.