Two new species of Paraehlersia San Martin, 2003 (Polychaeta, Syllidae) from the Atlantic Coast of South America

Paraehlersia San Martin, 2003 is reported for the first time for the Atlantic coast off South America based on specimens collected off Brazil and Argentina. The specimens belong to two new species, which are herein described. Paraehlersia longichaetosa sp. nov., is characterized by having spiniger-like chaetae with long blades, up to 120 mu m in length, bidentate anterior falcigers, with relatively coarse subdistal tooth, bidentate dorsal simple chaetae, with teeth about same size, and subdistally irregularly inflated aciculae, apparently hollow, with acute tip. Paraehlersia martapolae sp. nov., has spiniger-like chaetae with shorter blades, up to 82 mu m in length, bidentate falcigers, with thin subdistal tooth, distally irregularly rounded dorsal simple chaetae, and aciculae subdistally bent at almost right angle, sometimes with apparently flattened top. These new species are compared to their most similar congeners. Additionally, a table summarizing relevant morphological traits of all currently known species of Paraehlersia is included.

Characterization of suramin binding sites on the human group IIA secreted phospholipase A(2) by site-directed mutagenesis and molecular dynamics simulation

Suramin is a polysulphonated naphthylurea with inhibitory activity against the human secreted group IIA phospholipase A(2) (hsPLA2GIIA), and we have investigated suramin binding to recombinant hsPLA2GIIA using site-directed mutagenesis and molecular dynamics (MD) simulations. The changes in suramin binding affinity of 13 cationic residue mutants of the hsPLA2GIIA was strongly correlated with alterations in the inhibition of membrane damaging activity of the protein. Suramin binding to hsPLA2GIIA was also studied by MD simulations, which demonstrated that altered intermolecular potential energy of the suramin/mutant complexes was a reliable indicator of affinity change. Although residues in the C-terminal region play a major role in the stabilization of the hsPLA2GIIA/suramin complex, attractive and repulsive hydrophobic and electrostatic interactions with residues throughout the protein together with the adoption of a bent suramin conformation, all contribute to the stability of the complex. Analysis of the h5PLA2GIIA/suramin interactions allows the prediction of the properties of suramin analogues with improved binding and higher affinities which may be candidates for novel phospholipase A(2) inhibitors. (C) 2012 Elsevier Inc. All rights reserved.