The present disclosure provides a means for efficiently producing natural rubber and stably providing the same, and is aimed at stably providing a rubber resource. The present disclosure may provide a protein composition that exhibits an isoprene polymerization activity and comprises a protein(s) (B) exhibiting the same activity as CPTL and either one of proteins (A-1) exhibiting the same activity as CPT6 or (A-2) exhibiting the same activity as CPT7, as well as a lipid membrane structure comprising the composition, a method for producing the same, a cell expressing a protein constituting the composition, a method for producing the same, and a method for producing an isoprene polymer compound using any of the above.

Provided is a method for producing a polyisoprenoid, which can increase natural rubber production by enhancing the rubber synthesis activity of rubber particles. The present invention provides methods for producing a polyisoprenoid using a gene coding for a cis-prenyltransferase (CPT) family protein, a gene coding for a Nogo-B receptor (NgBR) family protein and a gene coding for a rubber elongation factor (REF) family protein, specifically a method for producing a polyisoprenoid in vitro using rubber particles bound to proteins coded for by these genes, and a method for producing a polyisoprenoid in vivo using a recombinant organism (plant) having these genes introduced therein.

Provided are a mutant cis-prenyltransferase (CPT) family protein and a method for producing a polyisoprenoid, which enable the production of a high molecular weight polyisoprenoid. Included is a mutant cis-prenyltransferase (CPT) family protein obtained by mutating the amino acid sequence of a N-terminal region of a cis-prenyltransferase (CPT) family protein not found on rubber particles to be identical or similar to the amino acid sequence of a N-terminal region of a cis-prenyltransferase (CPT) family protein found on rubber particles.

Provided are a mutant cis-prenyltransferase (CPT) family protein and a method for producing a polyisoprenoid, which enable the production of a high molecular weight polyisoprenoid. Included is a mutant cis-prenyltransferase (CET) family protein obtained by mutating the amino acid sequence of a N-terminal region of a cis-prenyltransferase (CPT) family protein not found on rubber particles to be identical or similar to the amino acid sequence of a N-terminal region of a cis-prenyltransferase (CPT) family protein found on rubber particles, and mutating the amino acid sequence of a C-terminal region of the cis-prenyltransferase (CPT) family protein not found on rubber particles to be identical or similar to the amino acid sequence of a C-terminal region of a cis-prenyltransferase (CPT) family protein found on rubber particles.

Provided are a mutant cis-prenyltransferase (CPT) family protein and a method for producing a polyisoprenoid, which enable the production of a high molecular weight polyisoprenoid. Included is a mutant cis-prenyltransferase (CPT) family protein obtained by mutating the amino acid sequence of a C-terminal region of a cis-prenyltransferase (CPT) family protein not found on rubber particles to be identical or similar to the amino acid sequence of a C-terminal region of a cis-prenyltransferase (CPT) family protein found on rubber particles.

Disclosed herein are recombinant enzymes derived from various rubber-producing plants and the use of those enzymes in the production of natural rubber outside of plant tissues. Systems and methods for the utilization of these enzymes in the production of natural rubber are also provided.

Provided is a method for producing a polyisoprenoid, which can increase natural rubber production by enhancing the rubber synthesis activity of rubber particles. The present invention provides methods for producing a polyisoprenoid using a gene coding for a cis-prenyltransferase (CPT) family protein, a gene coding for a Nogo-B receptor (NgBR) family protein and a gene coding for a rubber elongation factor (REF) family protein, specifically a method for producing a polyisoprenoid in vitro using rubber particles bound to proteins coded for by these genes, and a method for producing a polyisoprenoid in vivo using a recombinant organism (plant) having these genes introduced therein.

Provided is a method for producing a polyisoprenoid, which can increase natural rubber production by enhancing the rubber synthesis activity of rubber particles. The present invention provides methods for producing a polyisoprenoid using a gene coding for a cis-prenyltransferase (CPT) family protein, a gene coding for a Nogo-B receptor (NgBR) family protein and a gene coding for a rubber elongation factor (REF) family protein, specifically a method for producing a polyisoprenoid in vitro using rubber particles bound to proteins coded for by these genes, and a method for producing a polyisoprenoid in vivo using a recombinant organism (plant) having these genes introduced therein.

A rubber polymerase protein consisting of the amino acid sequence of SEQ ID NO: 2 for biosynthesis of natural rubber originating from a para rubber tree (Hevea brasiliensis). A gene encoding the rubber polymerase protein can be advantageously used for a technique of increasing a production amount of natural rubber from a rubber tree, a technique of producing natural rubber in other plants, microalgae, or microorganisms, or a technique for in vitro production of biorubber.

Provided are a transformant produced by introducing a gene coding for a cis-prenyltransferase and a gene coding for a Nogo-B receptor, which are considered to be involved in polyisoprenoid biosynthesis, into a host to allow the host to express the cis-prenyltransferase and the Nogo-B receptor, and a method for producing a polyisoprenoid using the transformant. The present invention relates to a transformant produced by introducing a gene coding for a cis-prenyltransferase and a gene coding for a Nogo-B receptor into a host to allow the host to express the cis-prenyltransferase and the Nogo-B receptor.