SecA functions in vivo as a discrete anti-parallel dimer to promote protein transport.

SecA ATPase motor protein plays a central role in bacterial protein transport by binding substrate proteins and the SecY channel complex and utilizing its ATPase activity to drive protein translocation across the plasma membrane. SecA has been shown to exist in a dynamic monomer-dimer equilibrium modulated by translocation ligands, and multiple structural forms of the dimer have been crystallized. Since the structural form of the dimer remains a controversial and unresolved question, we addressed this matter by engineering ρ-benzoylphenylalanine along dimer interfaces corresponding to the five different SecA X-ray structures and assessing their in vivo photo-crosslinking pattern.

The proteasome inhibitor MLN-273 blocks exoerythrocytic and erythrocytic development of Plasmodium parasites.

Protein degradation is regulated during the cell cycle of all eukaryotic cells and is mediated by the ubiquitin-proteasome pathway. Potent and specific peptide-derived inhibitors of the 20S proteasome have been developed recently as anti-cancer agents, based on their ability to induce apoptosis in rapidly dividing cells. Here, we tested a novel small molecule dipeptidyl boronic acid proteasome inhibitor, named MLN-273 on blood and liver stages of Plasmodium species, both of which undergo active replication, probably requiring extensive proteasome activity.

Commonly recognised Plasmodium falciparum parasites cause cerebral malaria.

Cerebral malaria (CM) is a devastating form of Plasmodium falciparum malaria, in which adherence and sequestration of infected red blood cells in cerebral blood vessels play a major role. In order to determine whether a distinct parasite phenotype favours the development of this severe complication, P. falciparum isolates from Gabonese children suffering from CM or uncomplicated malaria (UM) were analysed for their binding phenotypes and their recognition in flow cytometry.

Recognition of variant Rifin antigens by human antibodies induced during natural Plasmodium falciparum infections.

Antibodies from individuals living in areas where malaria is endemic are known to react with parasite-derived erythrocyte surface proteins. The major immunogenic and clonally variant surface antigen described to date is Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP-1), which is encoded by members of the multicopy var gene family. We report here that rifin proteins (RIF proteins), belonging to the largest known family of variable infected erythrocyte surface-expressed proteins, are also naturally immunogenic.

Identification and biochemical characterisation of a protein phosphatase 5 homologue from Plasmodium falciparum.

We report the identification of a new serine/threonine phosphatase from Plasmodium falciparum at the DNA and protein levels. A 1.8 kb cDNA fragment encoding the protein phosphatase was identified via PCR amplification.