Lys-373 of actin is involved in binding to caldesmon.
Limited proteolysis of actin with trypsin removes its two or three C-terminal amino acid residues [Proc. Natl. Acad. Sci. USA 81 (1984) 3680-3684]. Carboxypeptidase B-treatment of G- and F-actin previously digested with trypsin revealed that in the first case preferential release of three and in the second two C-terminal amino acid residues takes place. Tryptic removal of three but not two C-terminal amino acid residues of actin causes weakening of its interaction with caldesmon and lowering of the caldesmon-induced inhibitory effect on actomyosin ATPase activity. Therefore, it is concluded that the third amino acid residue from the C terminus of actin, Lys-373, is important for the interaction with caldesmon.
Kołakowski
J
J
Department of Muscle Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland.
Makuch
R
R
Dabrowska
R
R
D000199:Actins / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D002148:Calmodulin-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002645:Chickens; D010450:Endopeptidases; D008239:Lysine; D009132:Muscles / Q000201:enzymology; D010449:Peptide Mapping; D011817:Rabbits
D000199:Actins; D002148:Calmodulin-Binding Proteins; D010450:Endopeptidases; D000251:Adenosine Triphosphatases; D008239:Lysine