Engineered aryl sulfate-dependent enzymes
The present invention provides several non-naturally occurring sulfotransferase enzymes that have been engineered to react with aryl sulfate compounds as sulfo group donors, instead of the natural substrate 3′-phosphoadenosine 5′-phosphosulfate (PAPS), and with heparosan-based polysaccharides, particularly heparan sulfate, as sulfo group acceptors. Each of the engineered sulfotransferase enzymes have a biological activity characterized by the position within the heparosan-based polysaccharide that receives the sulfo group, including glucosaminyl N-sulfotransferase activity, hexuronyl 2-O sulfotransferase activity, glucosaminyl 6-O sulfotransferase activity, or glucosaminyl 3-O sulfotransferase activity. Methods of using the engineered sulfotransferases to produce sulfated heparosan-based polysaccharides, including polysaccharides having anticoagulant activity, are also provided.
1. A non-natural glucosaminyl 3-O sulfotransferase (3OST) enzyme having an amino acid sequence comprising multiple mutations relative to conserved amino acid residues and sequence motifs found in natural 3OST enzymes within enzyme class EC 2.8.2.23, wherein:
(a) the natural 3OST enzymes comprise the following conserved amino acid sequence motifs:
(i) a conserved amino acid sequence motif having the amino acid sequence of SEQ ID NO: 265; and
(ii) a conserved amino acid sequence motif having the amino acid sequence of SEQ ID NO: 267; and
(b) within the amino acid sequence of the non-natural 3OST enzyme,
(i) the conserved amino acid sequence motif having the amino acid sequence gf SEQ ID NO: 265 is mutated to SEQ ID NO: 268, and
(ii) the amino acid sequence of the non-natural 3OST enzyme comprises a mutated amino acid sequence motif having the amino acid sequence of SEQ ID NO: 269, and
(c) the non-natural 3OST enzyme has sulfotransferase activity in the absence of 3′-phosphoadenosine 5′-phosphosulfate, wherein the sulfotransferase activity comprises a transfer of a sulfo group from an aryl sulfate compound to N-,2-O,6-O-sulfated heparan sulfate to form an N-,2-O,3-O,6-O-sulfated heparan sulfate product.
2. The non-natural 3OST enzyme of claim 1 , wherein within the amino acid sequence of the non-natural 3OST enzyme, amino acid sequence SEQ ID NO: 267 is mutated to SEQ ID NO: 270.
3. The non-natural 3OST enzyme of claim 1 , wherein the non-natural 3OST enzyme comprises an amino acid sequence selected from the group consisting of SEQ ID NO: 154, SEQ ID NO: 155, SEQ ID NO: 156, SEQ ID NO: 157, SEQ ID NO: 158, SEQ ID NO: 159, and SEQ ID NO: 160.
4. The non-natural 3OST enzyme of claim 3 , wherein variable amino acid residues within SEQ ID NO: 154, defined as “X” are selected such that the non-natural 3OST enzyme has an amino acid sequence selected from the group consisting of SEQ ID NO: 147, SEQ ID NO: 149, and SEQ ID NO: 151.
5. The non-natural 3OST enzyme of claim 1 , wherein the amino acid sequence of the non-natural 3OST enzyme has at least 80% sequence identity with the amino acid sequence of a natural 3OST enzyme, the natural 3OST enzyme having an amino acid sequence selected from the group consisting of SEQ ID NO: 206 and SEQ ID NO: 220.
6. The non-natural 3OST enzyme of claim 1 , wherein the aryl sulfate compound is selected from the group consisting of p-nitrophenyl sulfate and 4-nitrocatechol sulfate.
7. A non-natural glucosaminyl 3-O sulfotransferase (3OST) enzyme engineered to have sulfotransferase activity in the absence of 3′-phosphoadenosine 5′-phosphosulfate (PAPS), the sulfotransferase activity comprising a transfer of a sulfo group from an aryl sulfate compound to heparan sulfate to form a 3-O-sulfated heparan sulfate product, wherein the heparan sulfate comprises N-,2-O,6-O-sulfated heparan sulfate, and the 3-O-sulfated heparan sulfate product comprises N-,2-O,3-O,6-O-sulfated heparan sulfate,
wherein the amino acid sequence of the non-natural 3OST enzyme comprises at east one amino acid sequence motif selected from the group consisting of SEQ ID NO: 268, SEQ ID NO: 269 and SEQ ID NO: 270.
8. The non-natural 3OST enzyme of claim 7 , wherein the non-natural 3OST enzyme has an amino acid sequence comprising multiple mutations relative to conserved amino acid residues found in natural 3OST enzymes within enzyme class EC 2.8.2.23, wherein:
natural 3OST enzymes have sulfotransferase activity with heparan sulfate and a sulfo group donor, the sulfo group donor consisting of PAPS, to form a 3-O-sulfated heparan sulfate product; and
the amino acid sequence of the non-natural 3OST enzyme has at least 80% sequence identity with the amino acid sequence of a natural 3OST enzyme, the natural 3OST enzyme amino acid sequence selected from the group consisting of SEQ ID NO: 206 and SEQ ID NO: 220.
9. The non-natural 3OST enzyme of claim 8 , wherein
the amino acid sequence of the non-natural 3OST enzyme comprises the amino acid sequence motif having the amino acid sequence of SEQ ID NO: 268.
10. The non-natural 3OST enzyme of claim 8 , wherein
the amino acid sequence of the non-natural 3OST enzyme comprises the amino acid sequence motif having the amino acid sequence of SEQ ID NO: 269.
11. The non-natural 3OST enzyme of claim 8 , wherein the aryl sulfate compound is selected from the group consisting of p-nitrophenyl sulfate and 4-nitrocatechol sulfate.
12. The non-natural 3OST enzyme of claim 7 , wherein the amino acid sequence of the non-natural 3OST enzyme comprises the amino acid sequence motif having the amino acid sequence of SEQ ID NO: 268.
13. The non-natural 3OST enzyme of claim 12 , wherein the amino acid sequence of the non-natural 3OST enzyme comprises the amino acid sequence motif having the amino acid sequence of SEQ ID NO: 269.
14. The non-natural 3OST enzyme of claim 13 , wherein the amino acid sequence of the non-natural 3OST enzyme comprises the amino acid sequence motif having the amino acid sequence of SEQ ID NO: 270.
15. The non-natural 3OST enzyme of claim 7 , wherein the amino acid sequence of the non-natural 3OST enzyme comprises the amino acid sequence motif having the amino acid sequence of SEQ ID NO: 269.
16. The non-natural 3OST enzyme of claim 7 , wherein the aryl sulfate compound is selected from the group consisting of p-nitrophenyl sulfate and 4-nitrocatechol sulfate.