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Andrew's Project Page - RISE summer 2000 |
Intern: Andrew Fisher, Chemistry, Dartmouth College
Mentor: Jan Sumerel
Faculty Supervisor: Dan Morse
Department: Biology |
Production of His-tagged silicatein a fused to green fluorescent protein and His-tagged red fluorescent protein.
The sponge, Thethya aurantia, produces large quantities of polymerized silica at ambient temperatures and pressures by biological mechanisms that are poorly understood. The siliceous spicules produced by this sponge contain a core axial protein filament that is layered with a highly repetitive silica structure. Three homologous protein subunits comprise the filament, and members of the laboratory named them silicateins (for silica proteins). They have dissociated these subunits to yield three similar subunits named, alpha, beta, and gamma. The most abundant of the subunits, silicatein alpha has been cloned and sequenced. Sequence analysis has revealed that this protein is highly similar to members of the Cathepsin L family of papain proteases. Using an in vitro assay at neutral pH, several members of Dr. Morse's lab have shown that silicateins catalyze the polymerization of silica and silsequioxanes from tetraethoxysilane and organically modified silicon triethoxides, respectively. It has been the goal of this work to engineer a chimera between silicatein-alpha and green fluorescent protein with a histidine tag in order to easily overproduce and purify fluorescent silicatein-alpha containing proteins in large quantities.
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