Van Eyk J E, Hodges R S
Medical Research Council Group in Protein Structure and Function, University of Alberta, Edmonton, Canada.
J Biol Chem. 1988 Feb 5;263(4):1726-32.
To systematically evaluate the contribution of each amino acid residue of the troponin I (TnI) inhibitory region (104-115), 14 synthetic analogs were synthesized by the solid-phase method. The analogs consisted of either single glycine or multiglycine replacements. The importance of the substituted amino acid(s) was determined from the extent of inhibition of the acto-S1 ATPase activity and the strength of binding to a troponin C (TnC) high pressure liquid chromatography affinity column of each synthetic analog. Every residue of the TnI sequence (104-115) is necessary to achieve maximum inhibition of the ATPase activity. However, the analogs quantitatively differed in the amount of inhibition induced. The TnI analogs bound less tightly to the TnC affinity column than the native synthetic peptide indicating that all residues in the TnI sequence contribute to the binding of TnC in the presence of Mg2+ or Ca2+. In the presence of Ca2+, there is a definite increase in the strength of the interaction between most analogs and TnC. This is accompanied with a shift toward a more specific interaction with the C terminus of the TnI inhibitory sequence.
为了系统评估肌钙蛋白I（TnI）抑制区域（104 - 115）每个氨基酸残基的作用，采用固相法合成了14种合成类似物。这些类似物由单个甘氨酸取代或多个甘氨酸取代组成。通过每种合成类似物对肌动蛋白 - S1 ATP酶活性的抑制程度以及与肌钙蛋白C（TnC）高压液相色谱亲和柱的结合强度，来确定取代氨基酸的重要性。TnI序列（104 - 115）的每个残基都是实现对ATP酶活性最大抑制所必需的。然而，这些类似物在诱导的抑制量上存在定量差异。与天然合成肽相比，TnI类似物与TnC亲和柱的结合不那么紧密，这表明在存在Mg2 +或Ca2 +的情况下，TnI序列中的所有残基都有助于TnC的结合。在存在Ca2 +的情况下，大多数类似物与TnC之间的相互作用强度有明显增加。这伴随着向与TnI抑制序列C末端更特异性相互作用的转变。
