EC Number   |
General Information |
Reference |
|---|
   4.2.3.30 | evolution |
enzymes KSLs belong to the type A/class I terpene synthase family |
746981 |
| 4.2.3.30 | evolution |
enzymes KSLs belong to the type A/class I terpene synthase family. The KSL5 members are clearly divided into two clades, representing japonica and indica groups. The KS responsible for gibberellin biosynthesis in a putative common ancestor, and OsKS1, which produces the tetracyclic ent-kaurene, has Ile as the corresponding key amino acid. Thus, it is suggested that substitution from Ile664 to Thr664 in KSL5 occurred before the onset of cultivation in the putative japonica ancestor. The OsKSL5 sequence is similar to the OsKSL6 sequence (89% identity), and it is therefore likely that the two KSL genes were generated through relatively recent duplication. The substitution in KSL5 probably occurred after duplication of the ancestral gene |
746981 |
| 4.2.3.30 | evolution |
in the plant kingdom, where the labdane-related diterpenoids (LRDs) are predominantly found, the class I and II diterpene cyclases seem to have most directly evolved via gene duplication and neofunctionalization of the ent-kaurene synthases (KSs) required in all vascular plants for gibberellin hormone biosynthesis. Accordingly, these enzymes are often termed KS-like (KSL) and form a distinct subfamily within the plant terpene synthase family. Like class I terpene synthases more generally, the KS(L)s carry out catalysis in a highly conserved alpha-helical bundle domain that contains two signature motifs. These DDxxD and NDxx(S/T)xxxE sequences are involved in ligation of a trinuclear Mg2+ cluster to promote substrate binding and the subsequent initiating ionization of the allylic diphosphate ester bond. Ile664 is conserved across all the known plant KSs, and substitution of Thr is found to similarly alter product outcome with the KS from not only rice (OsKS) but also the eudicot Arabidopsis thaliana (AtKS), leading to predominant production of ent-pimara-8(14),15-diene rather than ent-kaur-16-ene. OsKSL5 belongs to an early diverging KSL lineage within monocots and is relatively distantly related to any KSs |
746596 |
| 4.2.3.30 | malfunction |
substitution of Ile for the Thr found at this position in OsKSL5j does not lead to complete specificity for production of ent-isokaur-15-ene, as the resulting OsKSL5j:T664I also produces small amounts of ent-kaur-16-ene, along with more substantial amounts of ent-atiserene, resulting from alternative rearrangement of the ent-beyeran-12-yl+ intermediate formed by the second cyclization step |
746596 |
| 4.2.3.30 | more |
conserved residues at positions 661 (secondary) and 664 (primary) are responsible for substrate specificity. Two functionally distinct alleles of Oryza sativa OsKSL5, which react with ent-copalyl diphosphate (ent-copalyl diphosphate), with that from subspecies japonica (OsKSL5j) producing ent-pimara-8(14),15-diene and that from subspecies indica (OsKSL5i) producing ent-(iso)kaur-15-ene instead |
746596 |
| 4.2.3.30 | physiological function |
recombinant OrKSL5 converts ent-CDP to ent-pimara-8(14),15-diene (EC 4.2.3.30), whereas OrKSL5ind, OrKSL6 and OrKSL6ind all convert ent-CDP to ent-isokaurene (EC 4.2.3.103). The 664th amino acids of OrKSL5 and OrKSL5ind are Thr and Ile, respectively, as is the case for Oryza sativa OsKSL5 and OsKSL5ind |
746981 |
| 4.2.3.30 | physiological function |
the KSL5 members are clearly divided into two clades, representing japonica and indica groups, the 664th amino acids of OsKSL5j and OsKSL5i are Thr and Ile leading to different activity and production of ent-isokeurene synthase (EC 4.2.3.103) or ent-pimara-8(14),15-diene (EC 4.2.3.30) |
746981 |
