Engineered heme-binding compositions and uses thereof
Described herein are heme-binding compositions and methods relating to their use, for example methods of treatment of sepsis and rhabdomyolysis.
1. An engineered heme-binding molecule comprising a heme-binding domain of human hemopexin and a human IgG Fc domain; wherein the heme-binding domain is conjugated to the Fc domain; wherein the heme-binding domain comprises a polypeptide that is at least 90% identical to a sequence corresponding to residues 27-213 of SEQ ID NO: 2; and wherein the heme-binding domain binds to heme.
2. The engineered heme-binding molecule of claim 1 , wherein the heme-binding domain is at the N terminal of the Fc domain.
3. The engineered heme-binding molecule of claim 1 , wherein the heme-binding domain is at the C terminal of the Fc domain.
4. The engineered heme-binding molecule of claim 1 , further comprising a detectable label.
5. The engineered heme-binding molecule of claim 1 further comprising a microbe-binding domain.
6. The engineered heme-binding molecule of claim 5 , wherein the microbe-binding domain is selected from the group consisting of:
mannose-binding lectin (MBL) and C-reactive protein (CRP).
7. The engineered heme-binding molecule of claim 1 , wherein the heme-binding domain comprises a polypeptide that is at least 90% identical to a sequence corresponding to:
a) SEQ ID NO: 2;
b) residues 27-233 of SEQ ID NO: 2;
c) residues 1-233 of SEQ ID NO: 2;
d) residues 27-220 of SEQ ID NO: 2;
e) residues 1-220 of SEQ ID NO: 2; or
f) residues 1-213 of SEQ ID NO: 2.
8. The engineered heme-binding molecule of claim 1 , wherein the heme-binding domain comprises a mutation wherein the residues corresponding to residues 220-226 of SEQ ID NO: 2 have been replaced with a polypeptide linker of about 1-10 amino acids in length.
9. The engineered heme-binding molecule of claim 1 , wherein the heme-binding domain comprises a mutation wherein the residues corresponding to residues 220-226 of SEQ ID NO: 2 have been replaced with the sequence GSGS (SEQ ID NO: 18).
10. The engineered heme-binding molecule of claim 1 , wherein the Fc domain is a polypeptide having the sequence of SEQ ID NO: 8, SEQ ID NO: 7 or SEQ ID NO: 17.
11. The engineered heme-binding molecule of claim 1 having the sequence of SEQ ID NO: 3, SEQ ID NO: 4 or SEQ ID NO: 5.
12. The engineered heme-binding molecule of claim 1 , further comprising a linker or a substrate-binding domain.
13. The engineered heme-binding molecule of claim 12 , wherein the substrate-binding domain comprises alanine-lysine-threonine (AKT) (SEQ ID NO: 35).
14. The engineered heme-binding molecule of claim 1 , wherein the heme-binding domain comprises a polypeptide that is at least 90% identical to a sequence corresponding to:
a. residues 24-462 of SEQ ID NO: 1;
b. residues 24-256 of SEQ ID NO: 1;
c. residues 27-233 of SEQ ID NO: 1;
d. residues 1-233 of SEQ ID NO: 1;
e. residues 27-220 of SEQ ID NO: 1;
f. residues 1-220 of SEQ ID NO: 1;
g. residues 27-213 of SEQ ID NO: 1;
h. residues 1-213 of SEQ ID NO: 1;
i. residues 27-256 of SEQ ID NO: 1; or
j. residues 1-256 of SEQ ID NO: 1.
15. The engineered heme-binding molecule of claim 1 , wherein the heme-binding domain binds to heme and the Fc domain binds to an Fc receptor, thereby reducing the level of free heme or reducing the level of a molecule comprising heme in a solution.
16. The engineered heme-binding molecule of claim 15 , wherein the level of free heme or the level of the molecule comprising heme is reduced by at least 20%.
17. The engineered heme-binding molecule of claim 15 , wherein the level of free heme or the level of the molecule comprising heme is reduced by at least 95%.
18. The engineered heme-binding molecule of claim 15 , wherein the solution is blood.