The V-ATPase from etiolated barley (Hordeum vulgare L.) shoots is activated by blue light and interacts with 14-3-3 proteins.

The vacuolar

Mass Spectrometry in Clinical Microbiology and Infectious Diseases

Proteomic

Covalent attachment and Pro-Pro endopeptidase (PPEP-1)-mediated release of Clostridium difficile cell surface proteins involved in adhesion

Molecular basis of bacterial pathogenesis, virulence factors and antibiotic resistanc

Clostridium difficile sortase recognizes a (S/P)PXTG sequence motif and can accommodate diaminopimelic acid as a substrate for transpeptidation

Molecular basis of bacterial pathogenesis, virulence factors and antibiotic resistanc

Capillary-Electrophoresis Mass Spectrometry for the Detection of Carbapenemases in (Multi-)Drug-Resistant Gram-Negative Bacteria

Proteomic

A Novel Fic (Filamentation Induced by cAMP) Protein from Clostridium difficile Reveals an Inhibitory Motif-independent Adenylylation/AMPylation Mechanism

Filamentation induced by cAMP (Fic) domain proteins have been shown to catalyze the transfer of the AMP moiety from ATP onto a protein target. This type of post-translational modification was recently shown to play a crucial role in pathogenicity mediated by two bacterial virulence factors. Herein we characterize a novel Fic domain protein that we identified from the human pathogen Clostridium difficile. The crystal structure shows that the protein adopts a classical all-helical Fic fold, which belongs to class II of Fic domain proteins characterized by an intrinsic N-terminal autoinhibitory alpha-helix. A conserved glutamate residue in the inhibitory helix motif was previously shown in other Fic domain proteins to prevent proper binding of the ATP gamma-phosphate. However, here we demonstrate that both ATP binding and autoadenylylation activity of the C. difficile Fic domain protein are independent of the inhibitory motif. In support of this, the crystal structure of a mutant of this Fic protein in complex with ATP reveals that the gamma-phosphate adopts a conformation unique among Fic domains that seems to override the effect of the inhibitory helix. These results provide important structural insight into the adenylylation reaction mechanism catalyzed by Fic domains. Our findings reveal the presence of a class II Fic domain protein in the human pathogen C. difficile that is not regulated by autoinhibition and challenge the current dogma that all class I-III Fic domain proteins are inhibited by the inhibitory alpha-helix.Proteomic

Clostridium difficile secreted Pro-Pro endopeptidase PPEP-1 (ZMP1/CD2830) modulates adhesion through cleavage of the collagen binding protein CD2831

Proteomic

Discovery of a new Pro-Pro endopeptidase, PPEP-2, provides mechanistic insights into the differences in substrate specificity within the PPEP family

Molecular basis of bacterial pathogenesis, virulence factors and antibiotic resistanc

In-depth specificity profiling of endopeptidases using dedicated mix-and-split synthetic peptide libraries and mass spectrometry

Proteases comprise the class of enzymes that catalyzesthe hydrolysisof peptide bonds, thereby playing a pivotal role in many aspects oflife. The amino acids surrounding the scissile bond determine thesusceptibility toward protease-mediated hydrolysis. A detailed understandingof the cleavage specificity of a protease can lead to the identificationof its endogenous substrates, while it is also essential for the designof inhibitors. Although many methods for protease activity and specificityprofiling exist, none of these combine the advantages of combinatorialsynthetic libraries, i.e., high diversity, equimolar concentration,custom design regarding peptide length, and randomization, with thesensitivity and detection power of mass spectrometry. Here, we developedsuch a method and applied it to study a group of bacterial metalloproteasesthat have the unique specificity to cleave between two prolines, i.e.,Pro-Pro endopeptidases (PPEPs). We not only confirmed the prime-sidespecificity of PPEP-1 and PPEP-2, but also revealed some new unexpectedpeptide substrates. Moreover, we have characterized a new PPEP (PPEP-3)that has a prime-side specificity that is very different from thatof the other two PPEPs. Importantly, the approach that we presentin this study is generic and can be extended to investigate the specificityof other proteases.Molecular basis of virus replication, viral pathogenesis and antiviral strategie

A Novel Secreted Metalloprotease ( CD2830) from Clostridium difficile Cleaves Specific Proline Sequences in LPXTG Cell Surface Proteins

Cardiolog