7k14 | pdb_00007k14

Ternary soak structure of alkanesulfonate monooxygenase MsuD from Pseudomonas fluorescens with FMN and methanesulfonate

spinqualitylabelsall models 7k14, resolution 2.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7k14 is a 8 chain structure with sequence from Psepf. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 03S, CL, FMN, PO4 Related: 7jw9, 7jv3, 7jyb, 7k64 Gene: msuD, ssuD, Pfl01_3916 (PSEPF) Activity: Alkanesulfonate monooxygenase, with EC number 1.14.14.5 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [Q3K9A1_PSEPF] Catalyzes the desulfonation of aliphatic sulfonates.[HAMAP-Rule:MF_01229] Publication Abstract from PubMed Bacterial two-component flavin-dependent monooxygenases cleave the stable C-S bond of environmental and anthropogenic organosulfur compounds. The monooxygenase MsuD converts methanesulfonate (MS(-)) to sulfite, completing the sulfur assimilation process during sulfate starvation, but the mechanism of this conversion remains unclear. To explore the mechanism of C-S bond cleavage, we report a series of crystal structures of MsuD from Pseudomonas fluorescens in different liganded states. This report provides the first crystal structures of an alkanesulfonate monooxygenase with a bound flavin and alkanesulfonate, elucidating the roles of the active site lid, the protein C-terminus, and an active site loop in flavin and/or alkanesulfonate binding. These structures position MS(-) closest to the flavin N5 position, consistent with an N5-(hydro)peroxyflavin mechanism rather than a classical C4a-(hydro)peroxyflavin mechanism. A fully enclosed active site is observed in the ternary complex, mediated by interchain interaction of the C-terminus at the tetramer interface. These structures identify an unexpected function of the protein C-terminus in this protein family in stabilizing tetramer formation and the alkanesulfonate binding site. Spurred by interest from the crystal structures, we conducted biochemical assays and molecular docking that redefine MsuD as a small to medium chain alkanesulfonate monooxygenase. Functional mutations verify the sulfonate binding site and reveal the critical importance of the protein C-terminus for monooxygenase function. These findings reveal a deeper understanding of MsuD's functionality at the molecular level, and consequently how it operates within its role as part of the sulfur assimilation pathway. Structures of the alkanesulfonate monooxygenase MsuD provide insight into C-S bond cleavage, substrate scope, and an unexpected role for the tetramer.,Liew JJM, El Saudi I, Nguyen SV, Wicht DK, Dowling DP J Biol Chem. 2021 May 21:100823. doi: 10.1016/j.jbc.2021.100823. PMID:34029591 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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