Mutant ngal proteins and uses thereof
AssigneeThe Trustees of Columbia University in the City of New York
InventorsJonathan BARASCH, Andong QIU
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Abstract
In one aspect the present invention is directed to mutant Neutrophil gelatinase-associated lipocalin (NGAL) proteins that have the ability to bind to siderophores, such as enterochelin, and to chelate and transport iron, and that are excreted in the urine. Such NGAL mutants, and complexes thereof with siderophores, can be used to clear excess iron from the body, for example in the treatment of iron overload. The NGAL mutants of the invention also have antibacterial activity and can be used in the treatment of bacterial infections, such as those of the urinary tract.
Claims97
A mutant NGAL protein comprising an amino acid sequence that is at least 70% identical to the sequence of wild-type human NGAL (SEQ ID NO. 1), or a fragment thereof, wherein:
- (a) five or more residues from among Lys 15, Lys 46, Lys 50, Lys 59, Lys 62, Lys 73, Lys 74, Lys 75, Lys 98, His 118, Arg 130, Lys 149, and His 165 is mutated by deletion or by substitution with a non-positively charged amino acid residue, and
- (b) residues Asn 39, Ala 40, Tyr 52, Ser 68, Trp 79, Arg 81, Tyr 100, Tyr 106, Phe 123, Lys 125, Tyr 132, Phe 133, and Lysine 134 are either not mutated or are conservatively substituted,
- and wherein the mutant NGAL protein
- (c) is able to bind to a siderophore, and
- (d) is excreted in the urine.
A polypeptide that encodes a K3 NGAL protein and comprises an amino acid sequence that is identical to SEQ ID NO. 2.
A polypeptide that comprises an amino acid sequence that is at least 99% identical to SEQ ID No. 2, at least 95% identical to SEQ ID No. 2, at least 90% identical to SEQ ID No. 2, at least 80% identical to SEQ ID No. 2, or at least 70% identical to SEQ ID No. 2.
A K3 NGAL protein comprising an amino acid sequence that is identical to SEQ ID NO:
- 2, or a fragment thereof, wherein the K3 NGAL protein (a) is able to bind to a siderophore, and (b) is excreted in the urine.
A polypeptide that encodes a K3Cys protein and comprises an amino acid sequence that is identical to SEQ ID NO. 252.
A polypeptide that comprises an amino acid sequence that is at least 99% identical to SEQ ID No. 252, at least 95% identical to SEQ ID No. 252, at least 90% identical to SEQ ID No. 252, at least 80% identical to SEQ ID No. 252, or at least 70% identical to SEQ ID No. 252.
A K3Cys protein comprising an amino acid sequence that is identical to SEQ ID NO:
- 252, or a fragment thereof, wherein the K3Cys protein (a) is able to bind to a siderophore, and (b) is excreted in the urine.
A K3Cys mutant protein comprising an amino acid sequence that is at least 70% identical to the sequence of the K3Cys protein of SEQ ID NO:
- 252, or a fragment thereof, wherein:
- (a) residues Asn 39, Ala 40, Tyr 52, Ser 68, Trp 79, Arg 81, Tyr 100, Tyr 106, Phe 123, Lys 125, Tyr 132, Phe 133, and Lysine 134 are either not mutated or are conservatively substituted,
- and wherein the K3Cys mutant protein
- (b) is able to bind to a siderophore, and
- (c) is excreted in the urine.
Dependencies are inferred from the claim text.