https://www.selleckchem.com/products/akti-1-2.html We also improved the characterization of poorly described bacterial strains. #link# Our results highlight the advantage of addressing proteoforms rather than peptides for accurate bacterial characterization and qualify top-down proteomics as a promising tool in clinical microbiology. Data are available via ProteomeXchange with the identifier PXD019247.Suppression of protein aggregation is a subject of growing importance in the treatment of protein aggregation diseases, an urgent worldwide human health problem, and the production of therapeutic proteins, such as antibody drugs. We previously reported a method to identify compounds that suppress aggregation, based on screening using multiple terminal deletion mutants. We now present a method to determine the aggregation contact sites of proteins, using such solubilizing compounds, to design monodispersed mutants. We applied this strategy to the chemokine receptor-binding domain (CRBD) of FROUNT, which binds to the membrane-proximal C-terminal intracellular region of CCR2. Initially, the backbone NMR signals were assigned to a certain extent by available methods, and the putative locations of five α-helices were identified. Based on NMR chemical shift perturbations upon varying the protein concentrations, the first and third helices were found to contain the aggregation contact sites. The two helices are amphiphilic, and based on an NMR titration with 1,6-hexanediol, a CRBD solubilizing compound, the contact sites were identified as the hydrophobic patches located on the hydrophilic sides of the two helices. Subsequently, we designed multiple mutants targeting amino acid residues on the contact sites. Based on their NMR spectra, a doubly mutated CRBD (L538E/P612S) was selected from the designed mutants, and its monodispersed nature was confirmed by other biophysical methods. We then assessed the CCR2-binding activities of the mutants. Our method is useful for the prote