Arc1p是一個酵母菌tRNA結合蛋白質，它能與細胞質中的 glutamyl-tRNA synthetase（GluRSc）和 methionyl-tRNA Synthetase（MetRS）形成三元複合物。形成複合物可以顯著提高這兩種酵素對其相對應tRNA的胺醯化效率。最近的研究發現，Arc1p 的 N 端區域Lys86可以被轉譯後修飾，加上一個生物素(biotin)為了進一步研究生物素化(biotinylation)對Arc1p的結構及功能影響，我們進一步純化及比較野生型及突變型Arc1p的結構差異，結果發現發現:K86R和K86A突變完全阻斷了Arc1p生物素化，但是不會影響該蛋白質的細胞內功能，突變Arc1p仍能解救ARC1剔除株的cold sensitive外表型。然而，生物素化將會將影響Arc1p的熱穩定性，且 K86R在蛋白酶處理下看起來更耐受，而K86A更敏感。
關鍵詞：Arc1p，生物素化，K86R，K86A，突變;Abstract
Arc1p is a yeast-specific tRNA-binding protein that has ability to form a ternary complex with glutamyl-tRNA synthetase (GluRSc) and methionyl-tRNA synthetase (MetRS) in the cytoplasm. This complex can significantly enhance the aminoacylation efficiency of these two aaRSs to their respective cognate tRNAs. Recently, it was found that Arc1p can be biotinylated via post-translational modification at Lys86 (K86) in the N-domain. We herein studied the effect of K86 mutation on Arc1p’s structure and function. We found that mutation in K86R and K86A dramatically decreased the biotinylation level of Arc1p and altered its secondary structure. However, the mutant Arc1p could effectively rescue the cold-sensitive phenotype of an ARC1- strain, suggesting that biotinylation is dispensable for the rescue activity of Arc1p. Interestingly, K86R was more resistant to protease treatment than the wild-type, while K86A was more sensitive.
