Investigation of Metal-Binding Activity of Spider Coating Peptide (SCP-1)

Known for its tensile strength, spider silk can potentially be used industrially and medically. Spider silk is also extremely flexible, which gives it an added dimension for commercial possibilities. The cDNA under study, SCP-1, or spider coating peptide 1, was retrieved from a cDNA library prepared from the abdominal gland tissue of the Black Widow Spider, Lactrodectus hesperus. The SCP-1 peptide is coated on the surface of several different spider silk fiber types. Analysis of the translated cDNA for SCP-1 reveals five histidine residues clustered in the C-terminus of SCP-1. Based upon this observation, we hypothesize that SCP-1 binds to metal ions. To test this hypothesis, the SCP-1 cDNA was amplified via PCR and inserted into the plasmid, pBAD-TOPO. SCP-1 expression was induced in bacteria and its levels were monitored by western blot analysis. Western blot analysis showed that SCP-1 was expressed in high levels. To demonstrate that SCP-1 had metal binding ability, we tested the ability of SCP-1 to bind a nickel resin. Our studies demonstrate that SCP-1 can bind to nickel resin, suggesting it may potentially have antimicrobial activity.