Journal: Signal Transduction and Targeted Therapy

Article Title: Identification of heptapeptides targeting a lethal bacterial strain in septic mice through an integrative approach

doi: 10.1038/s41392-022-01035-6

Figure Lengend Snippet: Identification of VTK heptapeptide-targeted bacterial membrane proteins with label-free mass spectrometry. a Constrained principal coordinates analysis (cPCoA) plot. Protein profiles were determined by cPCoA distance among samples and characterized by close intragroup distances among samples. b Hierarchical clustering analysis of proteins from the HEE, VTK and input groups. The outer membrane proteins of MSI001 bacteria were digested with trypsin and pulled down by VTK or HEE heptapeptide as described in the Methods. Label-free mass spectrometry was used to quantitate proteins from the HEE, VTK and input groups. Red represents high expression, while blue represents low expression. c Volcano plot of proteins from the VTK group and HEE group. Red and green dots represent up- and downregulated proteins with |fold change (FC) | > 1.5 and P -value less than 0.05 compared to the control, respectively. d Protein sequence aliment of DEGQ and DEGP of E. coli MSI001 . The AAs with background color represent peptide fragments identified by mass spectrometry. e SPRi assay for the binding affinity between VTK peptide and DEGP or DEGQ protein. The synthesized VTK peptide (5 mmol/L, 10 µL) or HEE peptide as control was immobilized on an SPRi chip. DEGP or DEGQ protein at different concentrations (5 nmol/L, 10 nmol/L, 20 nmol/L) in solution flowed on an SPRi chip. Binding data were collected and analyzed by commercial SPRi analysis software (Plexera SPR Data Analysis Model, Plexera, USA). The K D values were obtained via the BIAevaluation Software version 4.1

Article Snippet: Binding data were collected and analyzed by SPR Data Analysis Module software (Plexera, USA).

Techniques: Mass Spectrometry, Expressing, Sequencing, Binding Assay, Synthesized, Software