5g1u
Linalool Dehydratase Isomerase in complex with Geraniol
Structural highlights
FunctionLDI_CASD6 Anaerobically catalyzes the stereospecific hydration of beta-myrcene to (3S)-linalool and the isomerization of (3S)-linalool to geraniol (PubMed:20663876, PubMed:28068311, Ref.8). Is thus involved in the initial steps of the anaerobic degradation of the monoterpene beta-myrcene (PubMed:20663876). Also catalyzes the reverse reactions, i.e. the isomerization of geraniol to linalool and the dehydration of linalool to myrcene (PubMed:20663876, PubMed:28068311, Ref.8). In this direction, the formation of myrcene from geraniol may be seen as a detoxification process for the monoterpene alcohol (PubMed:20663876). Shows a relatively broad substrate specificity and can use various geraniol and linalool derivatives (PubMed:28068311). Substrates required a specific alpha-methylallyl alcohol signature motif (PubMed:28068311). Neither the monoterpenes alpha- and beta-ocimene nor the monoterpenoids citronellol and nerol can be used as substrates (PubMed:20663876).[1] [2] [REFERENCE:8] Publication Abstract from PubMedThe asymmetric dehydration of alcohols is an important process for the direct synthesis of alkenes. We report the structure and substrate specificity of the bifunctional linalool dehydratase isomerase (LinD) from the bacterium Castellaniella defragrans that catalyzes in nature the hydration of beta-myrcene to linalool and the subsequent isomerization to geraniol. Enzymatic kinetic resolutions of truncated and elongated aromatic and aliphatic tertiary alcohols (C5-C15) that contain a specific signature motif demonstrate the broad substrate specificity of LinD. The three-dimensional structure of LinD from Castellaniella defragrans revealed a pentamer with active sites at the protomer interfaces. Furthermore, the structure of LinD in complex with the product geraniol provides initial mechanistic insights into this bifunctional enzyme. Site-directed mutagenesis confirmed active site amino acid residues essential for its dehydration and isomerization activity. These structural and mechanistic insights facilitate the development of hydrating catalysts, enriching the toolbox for novel bond-forming biocatalysis. Structural and functional insights into asymmetric enzymatic dehydration of alkenols.,Nestl BM, Geinitz C, Popa S, Rizek S, Haselbeck RJ, Stephen R, Noble MA, Fischer MP, Ralph EC, Hau HT, Man H, Omar M, Turkenburg JP, van Dien S, Culler SJ, Grogan G, Hauer B Nat Chem Biol. 2017 Jan 9. doi: 10.1038/nchembio.2271. PMID:28068311[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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