Abstract
ABSTRACT Gelsolin is a key regulator for action dynamics which has six homologous domains notated from G1 to G6. It has the ability for severing, disassembling, or capping the actin filaments. Reviewing relative literatures, there are two different reported structures of G2-G3 fragment for gelsolin. In this report, small-angle X-ray scattering (SAXS) has been applied to analyze structures of G2-G3 fragments from two different constructs. Each construct is composed of two tertiary domains G2 and G3, a flexible header and linker. The difference between the two constructs is the length of the flexible header. Both solution structures of the two constructs have been revealed by using the ab-initio method and rigid-body refinement. A comparison of the crystal and solution structures suggests that they are slightly different from each others. Moreover, the flexible header might interfere relative orientations of G2 and G3 domains. The other subject of interest is to reveal the solution structure of the actin-peptide complex, which is composed of three actins and one peptide. Actin participates in many important cellular processes, including muscle contraction, cell motility, maintenance of cell, and cell signaling. Peptide is a polymer of several amino acids. The two possible solution structures of actin-peptide complex have been reported by using SAXS analysis. Key words: SAXS, gelsolin, actin filament, protein solution structure