6zmg

PHAGE SAM LYASE IN COMPLEX WITH S-ADENOSYL-L-HOMOCYSTEINE

spinqualitylabelsall models 6zmg, resolution 1.48Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.48Å Ligands: PO4, SAH Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed The first S-adenosyl methionine (SAM) degrading enzyme (SAMase) was discovered in bacteriophage T3, as a counter-defense against the bacterial restriction-modification system, and annotated as a SAM hydrolase forming 5'-methyl-thioadenosine (MTA) and L-homoserine. From environmental phages, we recently discovered three SAMases with barely detectable sequence similarity to T3 SAMase and without homology to proteins of known structure. Here, we present the very first phage SAMase structures, in complex with a substrate analogue and the product MTA. The structure shows a trimer of alpha-beta sandwiches similar to the GlnB-like superfamily, with active sites formed at the trimer interfaces. Quantum-mechanical calculations, thin-layer chromatography, and nuclear magnetic resonance spectroscopy demonstrate that this family of enzymes are not hydrolases but lyases forming MTA and L-homoserine lactone in a unimolecular reaction mechanism. Sequence analysis and in vitro and in vivo mutagenesis support that T3 SAMase belongs to the same structural family and utilizes the same reaction mechanism. Structure and mechanism of a phage-encoded SAM lyase revises catalytic function of enzyme family.,Guo X, Soderholm A, Kanchugal P S, Isaksen GV, Warsi O, Eckhard U, Triguis S, Gogoll A, Jerlstrom-Hultqvist J, Aqvist J, Andersson DI, Selmer M Elife. 2021 Feb 10;10. pii: 61818. doi: 10.7554/eLife.61818. PMID:33567250 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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