4XLX: Crystal Structure Of Bjks From Bradyrhizobium Japonicum

Citation:
Abstract
We report the first X-ray crystal structure of ent-kaur-16-ene synthase from Bradyrhizobium japonicum, together with the results of a site-directed mutagenesis investigation into catalytic activity. The structure is very similar to that of the alpha domains of modern plant terpene cyclases, a result that is of interest since it has been proposed that many plant terpene cyclases may have arisen from bacterial diterpene cyclases. The ent-copalyl diphosphate substrate binds to a hydrophobic pocket near a cluster of Asp and Arg residues that are essential for catalysis, with the carbocations formed on ionization being protected by Leu, Tyr and Phe residues. A bisphosphonate inhibitor binds to the same site. In the kaurene synthase from the moss Physcomitrella patens, 16-alpha-hydroxy-ent-kaurane as well as kaurene are produced since Leu and Tyr in the P. patens kaurene synthase active site are replaced by smaller residues enabling carbocation quenching by water. Overall, the results represent the first structure determination of a bacterial diterpene cyclase, providing insights into catalytic activity, as well as structural comparisons with diverse terpene synthases and cyclases which clearly separate the terpene cyclases from other terpene synthases having highly alpha-helical structures.
PDB ID: 4XLXDownload
MMDB ID: 126776
PDB Deposition Date: 2013/5/20
Updated in MMDB: 2015/02
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 4XLX: dimeric; determined by author and by software (PISA)
Molecular Components in 4XLX
Label Count Molecule
Proteins (2 molecules)
2
Uncharacterized Protein Blr2150(Gene symbol: blr2150)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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