Cyclic peptide
A cyclic peptide ( 10 ) includes two domains (D 1 ,D 2 ), each including three charged sub-domains ( 14, 16 ). The first domain (D 1 ) includes two anionic sub-domains ( 14 ) followed by a cationic sub-domain ( 16 ). The second domain (D 2 ) includes two cationic sub-domains ( 16 ) followed by an anionic sub-domain ( 14 ). The two domains are connected to one another and separated by a tri-glycyl linker ( 12 ). The cyclic peptide ( 10 ) is able to self-assemble into a network able to mimic an extracelluar matrix, and which promotes cell growth while resisting biofilm formation.
1. A cyclic peptide including a first domain and a second domain, the first domain and the second domain connected to one another at each end by a linker, wherein each domain includes a plurality of charged sub-domains and includes at least one cationic sub-domain and at least one anionic sub-domain;
wherein an anionic sub-domain is located at the amino-end of the first domain and at the carboxyl-end of the second domain, and wherein the cationic sub-domain is located at the carboxyl-end of the first domain and the amino-end of the second domain; or
wherein the first domain comprises the sequence: EIAALEQEIAALEYKIAALK (SEQ ID NO.3) and/or the second domain comprises the sequence: KIAALKQKIAALKQEIAALE (SEQ ID NO.4).
2. A cyclic peptide as claimed in claim 1 , wherein within each of the first domain and the second domain there is not an equal number of cationic sub-domains and anionic sub-domains.
3. A cyclic peptide as claimed in claim 1 , wherein the first domain and the second domain include an odd number of sub-domains.
4. A cyclic peptide as claimed in 1 , wherein the first domain and the second domain do not have the same number of cationic sub-domains as one another, and wherein the first domain and the second domain do not have the same number of anionic sub-domains as one another.
5. A cyclic peptide as claimed in claim 1 , wherein the peptide has the formula:
((gabcdef) m (gabcde) n -(X) q (gabcdef) m (gabcde) n -(X) q )
where gabcdef is a heptad repeat motif, X is a flexible linker;
m≥2; n≥1; and q=1.
6. A cyclic peptide as claimed in claim 1 , having the sequence:
EIAALEQEIAALEYKIAALKGGGKIAALKQKIAALKQEIAALEGGG (SEQ ID NO.5).
7. A synthetic protein network formed from a cyclic peptide as claimed in claim 1 .
8. A synthetic protein network as claimed in claim 7 , wherein the network is a synthetic extracellular matrix.
9. A synthetic protein network as claimed in claim 7 , including eukaryotic cells grown thereon.
10. A synthetic protein network as claimed in claim 9 , wherein the eukaryotic cells are vertebrate cells.
11. A method of making a synthetic protein network, including providing a cyclic peptide as claimed claim 1 , and allowing the cyclic peptide to self-assemble into the synthetic protein network.
12. A synthetic protein network as claimed in claim 7 , wherein the network prevents bacterial adsorption, colonisation and biofilm formation.