A computational study of the interaction of the foot and mouth disease virus VP1 with monoclonal antibodies.

Foot and mouth disease is caused by a non-enveloped virus (FMDV), which disposes several antigenic sites at the surface of their capsid proteins. The most relevant and immunodominant antigenic site of FMDV (site A or AnSA) includes a key virus-cell interaction element (RGD motif) located in the Viral Protein 1 (VP1), more precisely at the GH loop. AnSA includes a set of overlapped and mainly linear epitopes, which are the main targets of the humoral immune response. Taking advantage over specific structural features of the GH loop, we have evaluated the influence of every amino acid residue at AnSA in the interaction with 2 neutralizing antibodies by molecular modeling techniques. Additionally, we constructed diverse interaction complexes with multiple site A mutants and discussed about the structural influence of amino acidic insertions in such relevant antigenic site of FMDV. Our approach is in agreement with previous ELISA experiments and allows the understanding of how FMDV mutations may alter the interaction with different antibodies, as we can estimate the contribution of each amino acid to the interaction. Overall, our work contributes to the development of specific vaccination strategies for FMD control.

The crystal structure of the MAP kinase LmaMPK10 from Leishmania major reveals parasite-specific features and regulatory mechanisms.

Mitogen-activated protein kinases (MAPKs) are involved in environmental signal sensing. They are thus expected to play key roles in the biology of Trypanosomatid parasites, which display complex life cycles and use extracellular cues to modulate cell differentiation. Despite their relevance, structural data of Trypanosomatid MAPKs is lacking. We have now determined the crystal structure of Leishmania major LmaMPK10, a stage-specifically activated MAPK, both alone and in complex with SB203580. LmaMPK10 was observed to be more similar to p38 than to other human MAPKs. However, significant differences could be identified in the catalytic pocket, as well as in potentially regulatory sites in the N-terminal lobe. The modified pocket architecture in LmaMPK10 precludes DFG-in/DFG-out regulatory flipping as observed in mammalian MAPKs. LmaMPK10-nucleotide association was also studied, revealing a potential C-terminal autoinhibitory mechanism. Overall, these data should speed the discovery of molecules interfering with LmaMPK10 functions, with relevance for antileishmanial drug development strategies.