Geranylgeranyl pyrophosphate synthases
The present invention relates a variant polypeptide having geranylgeranyl pyrophosphate synthase activity, which variant polypeptide comprises an amino acid sequence which, when aligned with a geranylgeranyl pyrophosphate synthase comprising the sequence set out in SEQ ID NO: 1, comprises at least one substitution of an amino acid residue corresponding to any of amino acids at positions 92, 100 or 235 said positions being defined with reference to SEQ ID NO: 1 and wherein the variant has one or more modified properties as compared with a reference polypeptide having geranylgeranyl pyrophosphate synthase activity. A variant polypeptide of the invention may be used in a recombinant host for the production of steviol or a steviol glycoside.
1. A variant polypeptide having geranylgeranyl pyrophosphate synthase activity, wherein the variant polypeptide comprises an amino acid sequence having at least 80% sequence identity with the amino acid sequence of SEQ ID NO:1 and which, when aligned with the amino acid sequence of SEQ ID NO:1, comprises a substitution of an amino acid residue corresponding to any of amino acids at positions 92, 100, or 235 with a different amino acid.
2. The variant polypeptide according to claim 1 which comprises at least one additional substitution at an amino acid position other than 92, 100, or 235.
3. The variant polypeptide according to claim 1 , wherein the variant polypeptide comprises an amino acid sequence having at least 85% sequence identity with the amino acid sequence of SEQ ID NO:1.
4. The variant polypeptide according to claim 1 , wherein the variant polypeptide comprises an amino acid sequence having at least 95% sequence identity with the amino acid sequence of SEQ ID NO:1.
5. The variant polypeptide of claim 1 , wherein the variant polypeptide comprises a substitution relative to SEQ ID NO:1 selected from the group consisting of A100V, A100G, A100F, A100Y, A100I, and A100L.
6. The variant polypeptide of claim 1 , wherein the variant polypeptide comprises a substitution relative to SEQ ID NO:1 selected from the group consisting of G92E, G92D, G92N, and G92Q.
7. The variant polypeptide of claim 1 , wherein the variant polypeptide comprises a substitution relative to SEQ ID NO:1 selected from the group consisting of S235N, S235A, S235G, S235Q, S235V, S235D, S235E, S235F, and S235Y.