Cloning, expression, purification, crystallization and preliminary crystallographic analysis of -filamin repeat 23
Human -filamin is a protein of 2705 amino-acid residues that localizes mainly in the myofibrillar Z-disc and to smaller extent in the subsarcolemmal region of striated muscle cells. -Filamin consists of an N-terminal actin-binding domain followed by a long rod-shaped region. The rod-shaped region consists of 24 immunoglobulin-like domains that form a platform for interaction with different transmembrane, cell-signalling and cytoskeletal proteins. -Filamin repeat 23 was indicated as being necessary for binding to the muscle-specific subsarcolemmal proteins - and -sarcoglycan and the myofibrillar protein FATZ1. The recombinant -filamin repeat 23 was crystallized using the hanging-drop vapour-diffusion method, which yielded needle-shaped diffraction-quality crystals. Diffraction data were collected to 2.05 Å resolution using 1.2 Å wavelength synchrotron radiation. Preliminary structural analysis shows one molecule, with predominantly secondary-structure elements, per asymmetric unit.