STRUCTURAL STUDIES OF JERDOSTATIN. A NOVEL SNAKE VENOM DISINTEGRIN Silvia Mosuléna, Libia Sanzb, Rodrigo J. Carbajoa, Juan José Calveteb, Antonio Pineda-Lucenaa aLaboratorio de Biología Estructural, firstname.lastname@example.org, Centro de Investigación Príncipe Felipe, Avda. Autopista del Saler 16-3, Valencia-46013, Spain;
bInstituto de Biomedicina de Valencia CSIC, C/ Jaime Roig 11, Valencia-46010, Spain
Disintegrins represent a family of polypeptides found in the venoms of various vipers that selectively block the function of the integrin receptors. The common characteristic feature to all disintegrins is the similar pattern of cysteines and the presence of the so-called "integrin-binding” loop. The integrin-inhibitory activity of disintegrins depends on the appropriate pairing of cysteine residues, which determines the conformation of the inhibitory loop.
Our work is centred on r-jerdostatin, a novel disintegrin from Trimeresurus jerdoniirecombinantly produced in E. coli. r-jerdostatin is a 43 amino acid polypeptide that functions as a specific antagonist of the α1β1 integrin. The distinct features of r-jerdostatin are located in the sequence of the integrin-binding loop and the C-terminal tail. r-jerdostatin presents a novel RTS motif in the binding loop, in contrast to the KTS sequence found in all other reported disintegrins that selectively target the α1β1 integrin. Additionally, it contains two extra C-terminal residues (Asn42Gly43) which in all venom-isolated members of the α1β1-specific short disintegrins are post-translationally removed. Although synthetic peptides bearing the RTS motif appears to be more potent than those possessing KTS inhibiting the α1β1 integrin, r-jerdostatin is less active than the KTS-disintegrins obtustatin (from Vipera lebetina obtusa), viperistatin (Vipera palestinae), and lebestatin (Macrovipera lebetina transmediterranea), strongly suggesting that substitutions outside the integrin-binding motif and C-terminal proteolytic processing are responsible for the decreased inhibitory activity1.
Here we present structural studies by NMR of wild type r-jerdostatin and mutants in the integrin-binding loop and C-terminal sequences of the protein, both regions considered responsible for the biological activity of the disintegrins.
1. Sanz, L., Chen, R.-Q., Pérez, A., Hilario, R., Juárez, P., Marcinkiewicz, C., Monleón, D., Celda, B., Xiong, Y.-L., Pérez-Payá, E., Calvete, J. J. J. Biol. Chem.280, 40714-40722 (2005).