6f7t
Crystal Structure of an Fab fragment in complex with a peptide from Bacillus subtilis RNase YCrystal Structure of an Fab fragment in complex with a peptide from Bacillus subtilis RNase Y
Structural highlights
FunctionRNY_BACSU Endoribonuclease that initiates mRNA decay. Initiates the decay of all SAM-dependent riboswitches, such as yitJ riboswitch. Involved in processing of the gapA operon mRNA, it cleaves between cggR and gapA (PubMed:19193632). Is also the decay-initiating endonuclease for rpsO mRNA.[1] [2] [3] [4] [5] Publication Abstract from PubMedAlthough RNase Y acts as the key enzyme initiating messenger RNA decay in Bacillus subtilis and likely in many other Gram-positive bacteria, its three-dimensional structure remains unknown. An antibody belonging to the rare immunoglobulin G (IgG) 2b lambdax isotype was raised against a 12-residue conserved peptide from the N-terminal noncatalytic domain of B. subtilis RNase Y (BsRNaseY) that is predicted to be intrinsically disordered. Here, we show that this domain can be produced as a stand-alone protein called Nter-BsRNaseY that undergoes conformational changes between monomeric and dimeric forms. Circular dichroism and size exclusion chromatography coupled with multiangle light scattering or with small angle x-ray scattering indicate that the Nter-BsRNaseY dimer displays an elongated form and a high content of alpha-helices, in agreement with the existence of a central coiled-coil structure appended with flexible ends, and that the monomeric state of Nter-BsRNaseY is favored upon binding the fragment antigen binding (Fab) of the antibody. The dissociation constants of the IgG/BsRNaseY, IgG/Nter-BsRNaseY, and IgG/peptide complexes indicate that the affinity of the IgG for Nter-BsRNaseY is in the nM range and suggest that the peptide is less accessible in BsRNaseY than in Nter-BsRNaseY. The crystal structure of the Fab in complex with the peptide antigen shows that the peptide adopts an elongated U-shaped conformation in which the unique hydrophobic residue of the peptide, Leu6, is completely buried. The peptide/Fab complex may mimic the interaction of a microdomain of the N-terminal domain of BsRNaseY with one of its cellular partners within the degradosome complex. Altogether, our results suggest that BsRNaseY may become accessible for protein interaction upon dissociation of its N-terminal domain into the monomeric form. Dissociation of the Dimer of the Intrinsically Disordered Domain of RNase Y upon Antibody Binding.,Hardouin P, Velours C, Bou-Nader C, Assrir N, Laalami S, Putzer H, Durand D, Golinelli-Pimpaneau B Biophys J. 2018 Oct 26. pii: S0006-3495(18)31164-0. doi:, 10.1016/j.bpj.2018.10.016. PMID:30447990[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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