Protein delivery to membranes

A method of labelling a cell with a protein label, comprising contacting a cell with a composition produced by a method comprising

• a. providing a protein-polymer surfactant conjugate;
• and
• b. contacting a phospholipid bilayer or micelle with the conjugate;
• wherein the protein-polymer surfactant conjugate comprises an anchor protein which is a cationised protein or an anionised protein and (i) is an enzyme and/or (ii) is a protein which does not comprise a —CH2C(O)NCH3(CH2)3N(CH3)2H+ linker covalently bonded to an amino acid side chain, and wherein the phospholipid bilayer forms the external membrane of the cell and the protein-polymer surfactant conjugate comprises the protein label.

A polypeptide comprising any of SEQ ID NOS:11, 13-16 or 40 or a functional variant of any of these having at least about 60% sequence identity with the non-variant sequence;

• or
• comprising a supercharged version of any of SEQ ID NOS:10, 19-22 or 25-39;
• or comprising a fusion protein of:
• a supercharged anchor protein and any of SEQ ID NOS:10 or 19-39;
• or a supercharged anchor protein and a functional variant of any of any of SEQ ID NOS:10 or 19-39 having at least 60% sequence identity thereto.