1VDJ:
reference: Structural Basis for Ca(2+)-regulated Muscle Relaxation at Interaction Sites of Troponin with Actin and Tropomyosin., Murakami K, Yumoto F, Ohki SY, Yasunaga T, Tanokura M, Wakabayashi T, J Mol Biol 2005 Sep 9;352(1):178-201. PMID: 16061251

This OCA Structure page
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