Glucosyltransferase enzymes for production of glucan polymers
View Patent ↗Compositions are disclosed herein comprising poly alpha-1,3-1,6-glucan with a weight average degree of polymerization (DP w ) of at least 1000. This glucan polymer comprises at least 30% alpha-1,3 linkages and at least 30% alpha-1,6 linkages. Further disclosed are glucosyltransferase enzymes that synthesize poly alpha-1,3-1,6-glucan. Ether derivatives of poly alpha-1,3-1,6-glucan and methods of using such derivatives as viscosity modifiers are also disclosed.
1. A reaction solution comprising water, sucrose and an isolated glucosyltransferase enzyme that synthesizes poly alpha-1,3-1,6-glucan, wherein said glucosyltransferase enzyme comprises an amino acid sequence that is at least 90% identical to SEQ ID NO:2, wherein:
(i) about 30%-40% of the glycosidic linkages of said glucan are alpha-1,3 linkages,
(ii) about 60%-70% of the glycosidic linkages of said glucan are alpha-1,6 linkages, and
(iii) said glucan has a weight average degree of polymerization (DP w ) of 10000 to 15000,
and wherein said glucan is insoluble in water and has no branch points.
2. The reaction solution of claim 1 , wherein said glucosyltransferase enzyme comprises an amino acid sequence that is at least 95% identical to SEQ ID NO:2.
3. The reaction solution of claim 2 , wherein said glucosyltransferase enzyme comprises an amino acid sequence that is at least 98% identical to SEQ ID NO:2.
4. The reaction solution of claim 3 , wherein said glucosyltransferase enzyme comprises the amino acid sequence of SEQ ID NO:2.
5. The reaction solution of claim 1 , wherein said glucosyltransferase enzyme consists of an amino acid sequence that is at least 90% identical to SEQ ID NO:2.
6. A method for producing poly alpha-1,3-1,6-glucan comprising:
contacting at least water, sucrose, and an isolated glucosyltransferase enzyme in a reaction solution, wherein said glucosyltransferase enzyme synthesizes poly alpha-1,3-1,6-glucan and comprises an amino acid sequence that is at least 90% identical to SEQ ID NO:2, whereby poly alpha-1,3-1,6-glucan is produced, wherein:
(i) about 30%-40% of the glycosidic linkages of said glucan are alpha-1,3 linkages,
(ii) about 60%-70% of the glycosidic linkages of said glucan are alpha-1,6 linkages, and
(iii) said glucan has a weight average degree of polymerization (DP w ) of 10000 to 15000,
and wherein said glucan is insoluble in water and has no branch points; and
b) optionally, isolating the poly alpha-1,3-1,6-glucan produced in step (a).
7. The method of claim 6 , wherein said glucosyltransferase enzyme comprises an amino acid sequence that is at least 95% identical to SEQ ID NO:2.
8. The method of claim 7 , wherein said glucosyltransferase enzyme comprises an amino acid sequence that is at least 98% identical to SEQ ID NO:2.
9. The method of claim 8 , wherein said glucosyltransferase enzyme comprises the amino acid sequence of SEQ ID NO:2.
10. The reaction solution of claim 5 , wherein said glucosyltransferase enzyme consists of an amino acid sequence that is at least 95% identical to SEQ ID NO:2.
11. The reaction solution of claim 10 , wherein said glucosyltransferase enzyme consists of an amino acid sequence that is at least 98% identical to SEQ ID NO:2.
12. The reaction solution of claim 1 , wherein said glucosyltransferase enzyme consists of the amino acid sequence of SEQ ID NO:2.
13. The reaction solution of claim 1 , wherein a heterologous amino acid sequence is at the N-terminus and/or C-terminus of said glucosyltransferase enzyme.
14. The reaction solution of claim 1 , wherein the reaction solution comprises only one of said glucosyltransferase enzyme.
15. The reaction solution of claim 1 , wherein the reaction solution is cell-free.