Gc (vitamin D-binding protein) binds the 33.5 K tryptic fragment of actin.
Limited proteolysis of G-actin was performed with trypsin and chymotrypsin to compare the binding sites for Gc and DNase. DNase I bound to the N-terminal area corresponding to the major cleavage site on G-actin (residues 62-68) and inhibited proteolysis, but did not bind the 33.5K C-terminal fragment (G-actin33.5) generated. In contrast, Gc did not exert any inhibitory effect upon proteolysis of the intact native G-actin42.0 molecule, although its presence protected G-actin33.5 from further proteolysis. This was shown by gel filtration to be due to the formation of complexes between Gc and G-actin33.5.
D000199:Actins / Q000378:metabolism*; D001665:Binding Sites; D002918:Chymotrypsin / Q000378:metabolism; D003851:Deoxyribonucleases / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D010446:Peptide Fragments / Q000378:metabolism*; D014357:Trypsin / Q000378:metabolism; D014809:Vitamin D-Binding Protein / Q000378:metabolism*
D000199:Actins; D010446:Peptide Fragments; D014809:Vitamin D-Binding Protein; D003851:Deoxyribonucleases; D002918:Chymotrypsin; D014357:Trypsin