NMR signal assignments afnd secondary structure determination of the N-terminal domain of the ribosome maturation factor M from Staphylococcus aureus

The ribosome maturation factor M (RimM) is a protein with a molecular mass of 19.072 kDa involved in assembling of the 30S ribosome subunit. The RimM is necessary for the efficient processing of 16S rRNA. However, the mechanism of interaction of the RimM N-terminal domain with 16S rRNA remains poorly studied. The synthesis of the N-terminal domain of RimM from Staphylococcus aureus enriched in 13 C and 15 N isotopes and subsequent analysis of chemical shifts of the 1 H, 13 C, and 15 N signals from the backbone and side chains are described. An analysis of chemical shifts suggests that the N-terminal domain of RimM contains six β-chains and three α-helices with the topology β1-β2-α1-β3-β4-β5-α2-β6-β3. The secondary structure of the N-terminal domain of RimM contains a KH domain between the β1 and β2 fold with a strongly conserved segment with the GXXG sequence. The further structural studies by integrated structural biology approach (NMR spectroscopy, X-ray diffraction analysis, and cryoelectron microscopy) of RimM and its complex with ribosome will allow screening of highly selective inhibitors of Staphylococcus aureus translation.