Literature summary for 2.5.1.21 extracted from

Kajikawa, M.; Kinohira, S.; Ando, A.; Shimoyama, M.; Kato, M.; Fukuzawa, H.
Accumulation of squalene in a microalga Chlamydomonas reinhardtii by genetic modification of squalene synthase and squalene epoxidase genes (2015), PLoS ONE, 10, e0120446.

Cloned(Commentary)

Cloned (Comment)	Organism
gene CrSQS, a single-copy gene, DNA and amino acid sequence determination and analysis, sequence comparisons, recombinant functional expression of C-terminally His6-tagged enzyme, with the hydrophobic transmembrane regions removed, in Escherichia coli. Transient expression of full-length GFP-tagged CrSQS and GFP-tagged squalene epoxidase CrSQE in onion epidermal tissue suggests that both proteins are co-localized in the endoplasmic reticulum. Overexpression of gene CrSQS in Chlamydomonas reinhardtii mutant strain UVM4 under the regulation of the constitutive PsaD promoter, squalene does not accumulate significantly in CrSQS-overexpressing cells, although conversion of farnesyl diphosphate to squalene is enhanced by overexpression of enzyme CrSQS	Chlamydomonas reinhardtii

Cloned (Comment)

Organism

gene CrSQS, a single-copy gene, DNA and amino acid sequence determination and analysis, sequence comparisons, recombinant functional expression of C-terminally His6-tagged enzyme, with the hydrophobic transmembrane regions removed, in Escherichia coli. Transient expression of full-length GFP-tagged CrSQS and GFP-tagged squalene epoxidase CrSQE in onion epidermal tissue suggests that both proteins are co-localized in the endoplasmic reticulum. Overexpression of gene CrSQS in Chlamydomonas reinhardtii mutant strain UVM4 under the regulation of the constitutive PsaD promoter, squalene does not accumulate significantly in CrSQS-overexpressing cells, although conversion of farnesyl diphosphate to squalene is enhanced by overexpression of enzyme CrSQS

Chlamydomonas reinhardtii

Protein Variants

Protein Variants	Comment	Organism
additional information	CrSQS-overexpression increases the rate of conversion of 14C-labeled farnesylpyrophosphate into squalene but does not lead to overaccumulation of squalene. Addition of terbinafine causes the accumulation of squalene and suppression of cell survival. In CrSQE-knockdown lines, the expression level of CrSQE is reduced by 59-76% of that in wild-type cells, and significant levels of squalene accumulate without any growth inhibition. In co-transformation lines with CrSQS-overexpression and squalene epoxidase CrSQE-knockdown, the level of squalene is not increased significantly compared with that in solitary CrSQE knockdown lines	Chlamydomonas reinhardtii

Localization

Localization	Comment	Organism	GeneOntology No.	Textmining
endoplasmic reticulum membrane	CrSQS protein has two putative transmembrane domains at the C-terminus, Phe398-Glu420 and Gln436-Leu458	Chlamydomonas reinhardtii	5789	-

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Mg2+	the enzyme requires either Mg2+ or Mn2+ as metal cofactor	Chlamydomonas reinhardtii
Mn2+	the enzyme requires either Mg2+ or Mn2+ as metal cofactor	Chlamydomonas reinhardtii

Molecular Weight [Da]

Molecular Weight [Da]	Molecular Weight Maximum [Da]	Comment	Organism
46000	-	-	Chlamydomonas reinhardtii
57000	-	-	Chlamydomonas reinhardtii

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
2 (2E,6E)-farnesyl diphosphate + NADPH + H+	Chlamydomonas reinhardtii	-	squalene + 2 diphosphate + NADP+	-	?

Organism

Organism	UniProt	Comment	Textmining
Chlamydomonas reinhardtii	-	gene CrSQS	-

Purification (Commentary)

Purification (Comment)	Organism
recombinant C-terminally His6-tagged and truncated enzyme from Escherichia coli by cobalt affinity chromatography	Chlamydomonas reinhardtii

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
2 (2E,6E)-farnesyl diphosphate + NADPH + H+	-	Chlamydomonas reinhardtii	squalene + 2 diphosphate + NADP+	-	?

Subunits

Subunits	Comment	Organism
?	x * 46000, recombinant C-terminally His6-tagged and truncated enzyme, SDS-PAGE, x * 57000, recombinant full-length enzyme, SDS-PAGE	Chlamydomonas reinhardtii

Synonyms

Synonyms	Comment	Organism
CrSQS	-	Chlamydomonas reinhardtii
SQS	-	Chlamydomonas reinhardtii

Cofactor

Cofactor	Comment	Organism	Structure
NADPH	dependent on	Chlamydomonas reinhardtii

General Information

General Information	Comment	Organism
metabolism	the enzyme is involved in squalene synthesis and sterol metabolism	Chlamydomonas reinhardtii
additional information	squalene does not accumulate significantly in CrSQS-overexpressing cells, although conversion of farnesyl diphosphate to squalene is enhanced by overexpression of enzyme CrSQS	Chlamydomonas reinhardtii
physiological function	the enzyme is involved in squalene synthesis and sterol metabolism	Chlamydomonas reinhardtii