Dimeric bacteriophage lysins
The present invention provides isolated dimeric Streptococcus -specific phage lysins having two Streptococcus -specific phage lysin monomers covalently linked to each other, and having killing activity against one or more Streptococcus bacteria. Also provided for are pharmaceutical compositions of dimeric lysins and their use in therapeutic treatment or alleviation of infections or bacterial colonizations. The dimeric lysins may also be used to decontaminate porous and non-porous surfaces or devices.
1. An isolated dimeric phage lysin comprising two phage lysin monomers specific for bacteria and capable of killing at least one or more Streptococcus bacteria covalently linked to each other, wherein said dimer has killing activity against one or more Streptococcus bacteria that is greater than the killing activity of any one of the phage lysin monomers, and wherein the lysin monomers are covalently associated or cross-linked via reactive groups or via amino acids in each monomer sequence at the C-terminus.
2. The lysin of claim 1 , wherein said lysin monomers are Cpl-1 monomers having at least 90% amino acid sequence identity to unmutated Cpl-1 SEQ ID NO: 1, or are Pal monomers having at least 90% amino acid sequence identity to unmutated Pal SEQ ID NO: 5.
3. The lysin of claim 1 , wherein said lysin monomers are chemically cross-linked to each other.
4. The lysin of claim 1 , wherein said lysin monomers are covalently linked to each other by a disulfide bond.
5. The lysin of claim 4 , wherein each monomer has a Cys residue that is between 14 and 20 amino acids from the C-terminus.
6. The lysin of claim 5 , wherein said lysin monomers do not have a Cys residue in the first 45 residues.
7. The lysin of claim 1 , wherein at least one of said lysin monomers comprise a catalytic domain of a first phage lysin specific for bacteria and capable of killing at least one or more Streptococcus bacteria and a binding domain of a second phage lysin specific for bacteria and capable of killing at least one or more Streptococcus bacteria.
8. The lysin of claim 7 , wherein the catalytic domain of a first phage lysin is the catalytic domain of Cpl-1 lysin amino acids 1-190 of SEQ ID NO: 1.
9. The lysin of claim 7 , wherein the binding domain of a second phage lysin is the binding domain of Cpl-1 lysin amino acids 191-326 of SEQ ID NO: 1, or the binding domain of Pal lysin amino acids 155-296 of SEQ ID NO: 5.
10. The lysin of claim 1 having killing activity against Streptococcus pneumoniae.
11. A method of treating a mammal suffering from a disease or condition caused by a streptococcal infection by administering a composition comprising a therapeutically effective amount of a lysin of claim 1 .
12. The method of claim 11 , wherein said infection is caused by Streptococcus pneumoniae.
13. The method of claim 11 , wherein said disease or condition is one or more diseases or conditions selected from the group of bacteremia, meningitis, pneumonia, otitis media, and sinusitis.
14. A method for decolonizing streptococcus in a mammal suffering from or at risk of a disease or condition caused by a streptococcal infection by administering a composition comprising a therapeutically effective amount of a lysin of claim 1 .
15. The method of claim 14 , wherein said infection is caused by Streptococcus pneumoniae.
16. A pharmaceutical composition comprising a therapeutically effective amount of a dimeric lysin of claim 1 , and a pharmaceutically acceptable carrier.
17. An anti-microbial composition for sanitizing or decontaminating porous or non-porous surfaces comprising a lysin of claim 1 .
18. A method for decontaminating inanimate surfaces suspected of containing infectious bacteria comprising treatment of said surfaces with a bacteriocidally or bacteriostatically effective amount of the composition of claim 16 .
19. The lysin of claim 1 , wherein said dimer has a longer half-life or reduced plasma clearance than any one of the phage lysin monomers.
20. The lysin of claim 1 , wherein said lysin monomers are cross-linked via a linker peptide or a heterologous peptide fused to their C-terminal ends or regions.