tailieunhanh - Báo cáo khoa hoc : Novel lynx spider toxin shares common molecular architecture with defense peptides from frog skin

A unique 30-residue cationic peptide oxyopinin 4a (Oxt 4a) was identified in the venom of the lynx spider Oxyopes takobius(Oxyopidae). Oxt 4a con-tains a single N-terminally located disulfide bond, Cys4–Cys10, and is structurally different from any spider toxin studied so far. | IFEBS Journal Novel lynx spider toxin shares common molecular architecture with defense peptides from frog skin Peter V. Dubovskii Alexander A. Vassilevski Olga V. Samsonova Natalya S. Egorova Sergey A. Kozlov Alexei V. Feofanov Alexander S. Arseniev and Eugene V. Grishin M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences Moscow Russia Keywords cytolytic peptide precursor Rana-box spatial structure spider venom A unique 30-residue cationic peptide oxyopinin 4a Oxt 4a was identified in the venom of the lynx spider Oxyopes takobius Oxyopidae . Oxt 4a contains a single N-terminally located disulfide bond Cys4-Cys10 and is Correspondence P. V. Dubovskii A. A. Vassilevski M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences ul. Miklukho-Maklaya 16 10 117997 Moscow Russia Fax 7 495 335 5033 7 495 330 7301 Tel 7 495 335 2733 7 495 336 6540 E-mail peter@ avas@. http structurally different from any spider toxin studied so far. According to NMR findings the peptide is disordered in water but assumes a peculiar torpedo-like structure in detergent micelles. It features a C-terminal amphipathic a-helical segment body residues 12-25 and an N-terminal disulfide-stabilized loop head residues 1-11 and has an unusually high density of positive charge in the head region. Synthetic Oxt 4a was produced and shown to possess strong and broad-spectrum cytolytic and antimicrobial activity. cDNA cloning showed that the peptide is synthesized in the form of a conventional prepropeptide with an acidic prosequence. Unlike other arachnid toxins Oxt 4a exhibits striking similarity with These authors contributed equally to this work defense peptides from the skin of ranid frogs that contain the so-called Rana-box motif a C-terminal disulfide-enclosed loop . Parallelism or convergence is apparent on several levels the structure function and biosyn- Received 6 July 2011 revised