Ferjani Imen, Fattoum Abdellatif, Maciver Sutherland K, Manai Mohamed, Benyamin Yves, Roustan Claude
UMR 5539 (CNRS) Laboratoire de motilité cellulaire (Ecole Pratique des Hautes Etudes) Université de Montpellier 2, Place E. Bataillon, CC107, 34095 Montpellier Cedex 5, France.
FEBS Lett. 2006 Sep 4;580(20):4801-6. doi: 10.1016/j.febslet.2006.07.065. Epub 2006 Aug 4.
Calponins are actin-binding proteins that are implicated in the regulation of actomyosin. Calponin binds filamentous actin (F-actin) through two distinct sites ABS1 and ABS2, with an affinity in the low micromolar range. We report that smooth muscle calponin binds monomeric actin with a similar affinity (K(d) of 0.15 microM). We show that the arrangement of binding is similar to that of F-actin by a number of criteria, most notably that the distance between Cys273 on calponin and Cys374 of actin is 29A when measured by fluorescent resonance energy transfer, the same distance as previously reported for F-actin.
钙调蛋白是一种肌动蛋白结合蛋白，参与调节肌动球蛋白。钙调蛋白通过两个不同的位点ABS1和ABS2与丝状肌动蛋白（F-肌动蛋白）结合，亲和力在低微摩尔范围内。我们报告平滑肌钙调蛋白以相似的亲和力（解离常数K(d)为0.15微摩尔）结合单体肌动蛋白。我们通过多种标准表明，其结合方式与F-肌动蛋白相似，最显著的是，通过荧光共振能量转移测量，钙调蛋白上的半胱氨酸273与肌动蛋白的半胱氨酸374之间的距离为29埃，与先前报道的F-肌动蛋白的距离相同。
