Functional domain of caldesmon.
Limited proteolysis of caldesmon has been used in studying the structure-function relationship of this protein. Digestion with alpha-chymotrypsin yields three major fragments of 110, 80 and 40 kDa. Only the 40 kDa fragment preserves functional properties of the parent molecule: it binds to F-actin, causes inhibition of actomyosin ATPase and binds to calmodulin in a Ca2+-dependent manner. Its further degradation produces an 18 kDa polypeptide that also retains all these properties. Neither F-actin nor calmodulin binding induces dramatic changes in susceptibility to chymotryptic cleavage and the sites of cleavage of caldesmon.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002147:Calmodulin / Q000378:metabolism; D002148:Calmodulin-Binding Proteins / Q000032:analysis*; D002645:Chickens; D002918:Chymotrypsin / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005895:Gizzard, Avian / Q000201:enzymology; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D011817:Rabbits; D013329:Structure-Activity Relationship
D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D010446:Peptide Fragments; D002918:Chymotrypsin; D000251:Adenosine Triphosphatases; D002118:Calcium