5t7d

Crystal structure of Streptomyces hygroscopicus bialaphos resistance (BAR) protein in complex with acetyl coenzyme A

spinqualitylabelsall models 5t7d, resolution 1.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5t7d is a 4 chain structure with sequence from Streptomyces hygroscopicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.4Å Ligands: ACO, ACT Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PAT_STRHY Inactivates phosphinothricin (PPT) by transfer of an acetyl group from acetyl CoA. Can also acetylate demethylphosphinothricin but not PTT or glutamate. This enzyme is an effector of phosphinothricin tripeptide (PTT or bialaphos) resistance. Publication Abstract from PubMed Bialaphos resistance (BAR) and phosphinothricin acetyltransferase (PAT) genes, which convey resistance to the broad-spectrum herbicide phosphinothricin (also known as glufosinate) via N-acetylation, have been globally used in basic plant research and genetically engineered crops (1-4) . Although early in vitro enzyme assays showed that recombinant BAR and PAT exhibit substrate preference toward phosphinothricin over the 20 proteinogenic amino acids (1) , indirect effects of BAR-containing transgenes in planta, including modified amino acid levels, have been seen but without the identification of their direct causes (5,6) . Combining metabolomics, plant genetics and biochemical approaches, we show that transgenic BAR indeed converts two plant endogenous amino acids, aminoadipate and tryptophan, to their respective N-acetylated products in several plant species. We report the crystal structures of BAR, and further delineate structural basis for its substrate selectivity and catalytic mechanism. Through structure-guided protein engineering, we generated several BAR variants that display significantly reduced non-specific activities compared with its wild-type counterpart in vivo. The transgenic expression of enzymes can result in unintended off-target metabolism arising from enzyme promiscuity. Understanding such phenomena at the mechanistic level can facilitate the design of maximally insulated systems featuring heterologously expressed enzymes. Non-specific activities of the major herbicide-resistance gene BAR.,Christ B, Hochstrasser R, Guyer L, Francisco R, Aubry S, Hortensteiner S, Weng JK Nat Plants. 2017 Dec;3(12):937-945. doi: 10.1038/s41477-017-0061-1. Epub 2017 Nov, 27. PMID:29180815 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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