Physarum tropomyosin-troponin complex. Isolation and properties.
The relaxing protein (TM-TN complex) was isolated from plasmodia of Physarum. SDS-gel electrophoresis revealed that the relaxing protein consists of tropomyosin subunits with a molecular weight of 35,000 troponin subunits with molecular weights of 38,000 (T) and 24,000 (I) and several other components. No component corresponding to muscle troponinC (MW-18,000) was detected in the plasmodium relaxing protein. The relaxing protein combined with muscle F-actin, and inhibited the ATPase [EC 3.6.1.3] activity and superprecipitation of reconstituted muscle actomysin in the absence of Ca2+ ions. The inhibition was reversed by adding 1 muM Ca2+ ions.
D000199:Actins / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D046911:Macromolecular Substances; D008970:Molecular Weight; D009119:Muscle Contraction; D009124:Muscle Proteins / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism; D009235:Myxomycetes / Q000378:metabolism*; D010804:Physarum / Q000378:metabolism*; D011485:Protein Binding; D011817:Rabbits; D014335:Tropomyosin / Q000302:isolation & purification / Q000378:metabolism*; D014336:Troponin / Q000302:isolation & purification / Q000378:metabolism*
D000199:Actins; D046911:Macromolecular Substances; D009124:Muscle Proteins; D014335:Tropomyosin; D014336:Troponin; D000251:Adenosine Triphosphatases; D002118:Calcium