抗肌萎縮蛋白(dystrophin)是連接F-肌動蛋白(F-actin)與肌肉細胞膜的一種蛋白質，主要功能在於穩定肌肉細胞膜使其免於肌肉拉伸所造成的損害。人體缺乏抗肌萎縮蛋白時會導致杜興氏肌肉營養不良症(Duchenne muscular dystrophy)，其病症為肌肉收縮時的肌肉無力和肌肉退化，肇因可能來自於抗肌萎縮蛋白與膜之間交互作用上的異常。抗肌萎縮蛋白由四個結構域(domain)所組成:與肌動蛋白連結結構域(actin binding amino-terminal domain)、包含24個血影蛋白樣重複區段(spectrin-like repeats)的棒狀結構域(rod domain)、與膜連結並富含半胱氨酸(cysteine)的錨定結構域(cysteine-rich membrane-binding anchor domain)以及C末端結構域(C-terminal domain)。先前的研究指出，特定之抗肌萎縮蛋白之棒狀結構域會與脂質膜產生相互作用，因此具有生物功能上的重要性。然而，這類研究皆是使用不含錨定域的抗肌萎縮蛋白異構體來進行。為了探討錨定域對抗肌萎縮蛋白與膜間之交互作用的影響、並更真實地模擬生物系統，本研究使用棕櫚酸作為抗肌萎縮蛋白異構體之錨定域。此錨定域成功並有效地增強了抗肌萎縮蛋白異構體與膜之間的結合作用，但作用過程中，脂質膜的結構並沒有明顯的改變。錨定域對於抗肌萎縮蛋白異構體與脂質膜之間的作用能力已在此研究中被證實，但背後的機制仍未被完全了解。;Dystrophin is a protein which connects the F-actin (a composing protein of microfilaments) and muscle cell membrane through the protein complex. Lack of dystrophin will lead to Duchenne muscular dystrophy (DMD), which features muscle weakness and muscle degeneration and may involve the abnormality of the dystrophin-membrane interactions. The dystrophin is composed of four domains: an actin binding domain, a rod domain comprising 24 spectrin-like repeats, a cysteine-rich domain and a C-terminal domain. In recent decades, some specific repeats of rod domain were demonstrated to interact with lipid membranes. But those experiments were done in a compromising condition which using dystrophin isoform without the anchor part. To explore how the presence of anchor domain affects the dystrophin-membrane interactions and to more resemble a real living system, we introduce a palmitic acid onto C-terminal of dystrophin isoform to serve as an anchor. The anchor make a pronounced effect in our series of experiments, which intensely reinforces the binding ability of dystrophin isoform to the lipid membrane. But the conformation of membrane wasn’t change obviously during the interaction. Although the excellent effect of palmitic acid anchor had been proved in this study. The mechanism working inside is still a puzzle waited to be unrevealed.
