CRUI: An Integrative Study of Spider Silk Proteins and Prey Capture

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9711031 Moore This spider silk study will determine molecular sources of the mechanical properties that facilitate prey capture in orb, funnel and cob webs. The wide array of material properties found in spider silks offers an ideal system for correlating material properties with molecular structure within a single class of biopolymers. This project will recruit undergraduates to research in biology, chemistry, physics and engineering at the Joint Science Department of the Claremont Colleges. Early exposure to crossdisciplinary research will enable students to bring a valuable viewpoint to their chosen careers. Silks from the funnel weaver, Hololena, and the cob weaver, Latrodectus mactans, will be compared to the known silks of the orb weaver, Araneus. This comparison will integrate information from five hierarchical levels: 1. primary structure from amino acid analysis, protein sequencing and gene expression; 2. secondary structure from carbon13 NMR spectroscopy; 3. higher order structure from atomic force microscopy; 4. mechanical properties from materials testing, and; 5. mechanical behavior of the whole web from computational modeling. Prey capture results from the integrated function of these silks and webs. Moreover, the understanding of relationships between material properties and molecular structure has implications for design of ideal materials. This project has been designed to enable undergraduates at Scripps, Pitzer and Claremont McKenna Colleges to collaborate with faculty in the study of spider webs and silk from three different spiders. Early exposure to inter disciplinary research will bring a valuable viewpoint to students' chosen careers. Not all spiders weave orb webs, although the familiar, circular orb web has been most often studied by scientists. Other webs are built in different shapes and also catch insects differently. Three web types will be studied: funnel webs built by the spider Hololena, the cob webs of the b lack widow spider (Latrodectus mactans), and orb webs of Araneus. Because these webs capture prey in distinct ways, the silk from each web type is expected to have different mechanical and molecular properties. The various webs and silks will be studied on five different levels. 1. Computers will be used to model the vibrations of the webs when prey is caught. 2. The strength and elasticity of the silks will be measured. 3. The structure of the silk fibers will be studied using a recently developed instrument called the atomic force microscope (AFM) which can image smaller than traditional microscopes. 4. Nuclear magnetic resonance (NMR) spectroscopy will be used to determine the folding and twisting of the silk proteins that may give the silks their strength and elasticity. 5. The chemical makeup of the silk proteins will be found by amino acid analysis. The understanding of relationships between material properties and molecular structure of silk proteins, in addition to being scientifically interesting, has implications for the design of new materials.