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Structural characterization of spider coating petide [i.e., peptide] 1 and 2 of the black widow spider, Latrodectus hesperus

Author

Nhu Thao Lisa Pham, University of the Pacific

Date of Award

2013

Document Type

Thesis - Pacific Access Restricted

Degree Name

Master of Science (M.S.)

Department

Biological Sciences

First Advisor

Craig A. Vierra

First Committee Member

Lisa A. Wrischnik

Second Committee Member

Marcos Gridi-Papp

Abstract

Spider silk is one of the most versatile material.s in nature with great mechanical properties, exceeding some of the best man made materials. Native and synthetically produced silk has been used in a wide array of applications throughout the history of mankind including nets, bandages and cloths. It is recognized that spider silk can be a suitable replacement material for many existing materials such as ropes, body armor, parachutes and biodegradable bottles - all of which could show cost and environmental 4 benefits relative to other currently used man made materials. An added advantage to these types of applications is the potential for the products to have intrinsic antimicrobial activity. Studies have demonstrated a level of antimicrobial activity in native silk, a property that may have evolved in order to resist microbial decomposition, to protect developing eggs, and to resist decomposition or destruction by predators, parasites, or fluctuations in the environment.

In this study, the novel aqueous glue coating peptides found on the silk fiber of the black widow spider, spider coating peptide 1 and 2, were investigated. Using circular dichroism, it was determined that SCP-1 and SCP-2 display predominantly alpha-helical secondary structures. In temperature gradient studies, SCP-1 is structurally stable at high temperatures while SCP-2 unfolded and lost its alpha-helical structure. The two peptides remained structurally stable both in an acidic and basic environment. This study was the first to characterize the secondary structure of the peptides found coating various silk fibers in Latrodectus hesperus, the black widow spider.

The function of the SCPs is unknown but has-been hypothesized to potentially have antimicrobial properties. We investigated this role and found no significant antibacterial activity of the peptides against Escherichia coli and Bacillus subtitlis in growth studies. This study is the first to investigate the functional role of SCPs.

Pages

83

Recommended Citation

Pham, Nhu Thao Lisa. (2013). Structural characterization of spider coating petide [i.e., peptide] 1 and 2 of the black widow spider, Latrodectus hesperus. University of the Pacific, Thesis - Pacific Access Restricted. https://scholarlycommons.pacific.edu/uop_etds/852