5i8f

Crystal structure of St. John's wort Hyp-1 protein in complex with melatonin

spinqualitylabelsall models 5i8f, resolution 1.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5i8f is a 1 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, ML1, NA, UNL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Publication Abstract from PubMed Hypericin, a red-colored naphtodianthrone, is a natural product synthesized in the medicinal plant Hypericum perforatum, widely known as St. John's wort. Hypericin has been attracting a growing attention of the pharmaceutical industry because of its potential application in various therapies, including the treatment of depression. In vivo, hypericin is synthesized by dimerization of emodin in a complicated multistep reaction that is reportedly catalyzed by a small (17.8kDa) protein, Hyp-1. Based on relatively low sequence similarity ( approximately 50%), Hyp-1 has been tentatively classified as a plant PR-10 (pathogenesis-related class 10) protein. Members of the PR-10 family are ubiquitous plant proteins associated with stress control and tissue differentiation but with no clearly understood molecular mechanism. They have, however, a well-defined folding canon, consisting of an extended antiparallel beta-sheet wrapped around a C-terminal alpha-helix, enclosing in the protein interior a huge cavity, in which various hydrophobic ligands can be bound. Apart from Hyp-1, only two other PR-10 members have been found to possess enzymatic activity (S-norcoclaurine synthase and TcmN aromatase/cyclase). In this paper, we report a high-resolution crystal structure of Hyp-1, confirming that it indeed has a PR-10 fold. The protein binds multiple polyethylene glycol molecules, some of which occupy the hydrophobic cavity. The crystallographic model illustrates a high degree of conformational adaptability of both interacting partners for efficient binding. We have been unable, however, to dimerize emodin to hypericin using Hyp-1 as biocatalyst. This puzzling result does not have a clear explanation at this time. Crystal structure of Hyp-1, a St. John's wort protein implicated in the biosynthesis of hypericin.,Michalska K, Fernandes H, Sikorski M, Jaskolski M J Struct Biol. 2010 Feb;169(2):161-71. Epub 2009 Oct 21. PMID:19853038 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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