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 Streptococcus -specific phage lysin comprising two Streptococcus -specific phage lysin monomers 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 Streptococcus -specific phage lysin monomers, and wherein each lysin monomer is mutated to contain a Cys residue between 14 and 20 amino acids from the C-terminus.
2. An isolated dimeric Streptococcus -specific phage lysin comprising two Streptococcus -specific phage lysin monomers 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 Streptococcus -specific phage lysin monomers, and wherein said lysin monomers are selected from Cpl-1 monomer having at least 90% amino acid sequence identity to unmutated Cpl-1 having the amino acid sequence SEQ ID NO: 1 and Pal monomer having at least 90% amino acid sequence identity to unmutated Pal having the amino acid sequence SEQ ID NO: 5, wherein each lysin monomer is mutated to contain a Cys residue between 14 and 20 amino acids from the C-terminus.
3. The lysin of claim 1 , wherein said lysin monomers are chemically cross-linked to each other.
4. The lysin of claim 2 , wherein said lysin monomers are covalently linked to each other by a disulfide bond.
5. The lysin of claim 2 , wherein said lysin monomers do not have a Cys residue in the first 45 residues.
6. The lysin of claim 2 , wherein said lysin monomers are selected from mutant Cpl-1 lysin comprising the amino acid sequence of SEQ ID NO: 1, wherein SEQ ID NO: 1 is mutated to contain a Cys residue between 14 and 20 amino acids from the C-terminus, and mutant Cpl-1 lysin comprising the amino acid sequence set out in SEQ ID NO: 3, mutant Pal lysin comprising the amino acid sequence of SEQ ID NO: 5, wherein SEQ ID NO: 5 is mutated to contain a Cys residue between 14 and 20 amino acids from the C-terminus, and mutant Pal lysin comprising the amino acid sequence set out in SEQ ID NO: 6.
7. The lysin of claim 1 , wherein said lysin monomers comprise a catalytic domain of a first Streptococcus -specific phage lysin and a binding domain of a second Streptococcus -specific phage lysin.
8. The lysin of claim 7 , wherein the catalytic domain of a first Streptococcus -specific phage lysin is the catalytic domain of Cpl-1 lysin amino acids 1-190 of SEQ ID NO: 1, or the catalytic domain of Pal lysin amino acids 1-150 of SEQ ID NO: 5.
9. The lysin of claim 7 , wherein the binding domain of a second Streptococcus -specific 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 151-296 of SEQ ID NO: 5.
10. The lysin of claim 1 or 2 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 or 2 .
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 or 2 .
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 or 2 , 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 or 2 .
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 .