Title: C‐terminally deleted fragments of 40‐kDa earthworm actin modulator still show gelsolin activities
Abstract: C‐ and N‐terminally truncated fragments of earthworm gelsolin were constructed, cloned and expressed in Escherichia coli . G‐actin‐binding properties of these fragments and their influences on the polymeric state of actin were investigated. A construct lacking a large part of the third segment [E(1–295)] supports actin nucleation similar to the complete protein and shows reduced actin fragmentation property, but is no longer Ca 2+ ‐sensitive in its activity. The first and the second segments (E1 and E2) each contain one actin‐binding site. In contrast to human gelsolin, E1 in combination with a short N‐terminal region of E2 is not sufficient for the F‐actin‐severing activity of the protein.