Strictosidine Synthase: Difference between revisions

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Santosh Panjikar, Michal Harel, Alexander Berchansky

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-<applet load="2fp8" size="300" color="white" frame="true" align="right" spinBox="true" />
+<StructureSection load='2fpb' size='350' side='right' caption='Strictosidine synthase dimer complex with tryptamine (PDB entry [[2fpb]])' scene='10/100149/Cv/3'>
-strictosidine synthase (EC 4.3.3.2) is an enzyme that catalyzes the chemical reaction
--alpha(S)-strictosidine + H2O \rightleftharpoons tryptamine + secologanin
+== Function ==
+The enzyme '''strictosidine synthase''' (<scene name='Strictisidine_Synthase/Str1_sp/1'>STR1</scene>) (EC 4.3.3.2) from an Indian medicinal plant ''Rauvolfia serpentina'' is of primary importance for the biosynthetic pathway of the indole alkaloid ajmaline. STR1 initiates all biosynthetic pathways leading to the entire monoterpenoid indole alkaloid family representing an enormous structural variety of ~2000 compounds in higher plants. The enzyme is involved in the biosynthesis of all these alkaloids by catalyzing the condensation of the two initial building blocks, tryptamine and the monoterpenoid secologanin, leading to the glucoalkaloid strictosidine. The reaction type catalyzed by STR1 is so far an exceptional example in the biosynthesis of natural products. It was hitherto known only from synthetic chemistry (Pictet-Spengler–type reaction), where it is applied in alkaloid synthesis, especially of tetrahydroisoquinolines by condensation of an amine and an aldehyde under acidic conditions<ref>PMID:18280746</ref>.
-Thus, the two substrates of this enzyme are 3-alpha(S)-strictosidine and H2O, whereas its two products are tryptamine and secologanin.
+The overall structure of the enzyme contains a six-bladed four-stranded ß-propeller fold. All six blades are radially arranged around a pseudo six-fold symmetry axis. Each blade contains a twisted four-stranded antiparallel ß-sheet.
-This enzyme belongs to the family of lyases, specifically amine lyases, which cleave carbon-nitrogen bonds. The systematic name of this enzyme class is 3-alpha(S)-strictosidine tryptamine-lyase (secologanin-forming). Other names in common use include strictosidine synthetase, STR, and 3-alpha(S)-strictosidine tryptamine-lyase. This enzyme participates in terpenoid biosynthesis and indole and ipecac alkaloid biosynthesis.
+== Structural highlights ==
+The <scene name='10/100149/Cv/8'>substrate binding pocket of STR1 is located near the pseudo six-fold symmetry axis</scene><ref>PMID:16531499</ref>. {{Template:ColorKey_Helix}},
+{{Template:ColorKey_Strand}},
+{{Template:ColorKey_Loop}},
+{{Template:ColorKey_Turn}}. <scene name='10/100149/Cv/9'>Active site</scene>. Water molecule are shown as red sphere.
+</StructureSection>
+==3D structures of strictosidine synthase==
+Updated on {{REVISIONDAY2}}-{{MONTHNAME|{{REVISIONMONTH}}}}-{{REVISIONYEAR}}
+[[2fp8]] – sSTR1 – serpentwood<br />
+[[3v1s]] – dSTR - devilpepper<br />
+[[2fp9]] – sSTR1 + tartaric acid
+[[2fpb]] – sSTR1 (mutant) + tryptamine
+[[2fpc]] – sSTR1 + secologanin
+[[2v91]] – sSTR1 residues 32-333 + strictosidine
+[[2vaq]] – sSTR1 + inhibitor<br />
+[[6n5v]], [[7t5i]], [[7t5j]] – sSTR + indole derivative <br />
+[[4imb]], [[4iyg]] – dSTR + indole derivative <br />
+[[6s5q]], [[6s5u]], [[6s5j]], [[6s5m]] – STR + carboline derivative – ''Ophiorrhiza pumila''<br />
+[[6zea]] – STR + carboline derivative – periwinkle<br />
+== References ==
+<references/>
+[[Category: Topic Page]]