Spider silks have remarkable physical properties due to a combination of strength and elasticity. In addition, spider silks are biocompatible and biodegradable. Our laboratory has shown that the strength of products, such as fibers, produced with other silk proteins correlates with the size of the silk protein. The aciniform silk protein (AcSp1), has been shown to produce the thinnest and strongest fibers of all the natural spider silks. Aciniform silk is composed of a nonrepetitive amino-terminal region, 14 repeats of approximately 200 amino acids each, and a nonrepetitive carboxy-terminal region. We have been able to produce different variants of this gene. All AcSp1 protein variants were able to express in E. coli. The bacteria expression of the AcSp1 protein is low and the protein is expressed not only as a full length polypeptide but also as fragments of the protein. We identified a sequence in the amino-terminal region of the first repeat of the AcSp1 gene that acts as an early termination sequence. Our objective is to modify this region on the gene to study changes in the expression efficiency of AcSp1
