新型 Na+/H+ 逆向转运蛋白 RDD 的 α2 螺旋 K101 残基突变

摘要

RDD 蛋白是一类至少以同源二聚体形式存在,并以寡聚体行使功能的新型 Na⁺(Li⁺,K⁺)/H⁺ 逆向转运蛋白,属于 RDD 家族,具有转运 Na⁺、Li⁺ 和 K⁺ 的功能。为鉴定 RDD 蛋白 α2 螺旋中高度保守的氨基酸残基 K101 是否在 RDD 寡聚化及转运功能维持中发挥重要作用,通过氨基酸定点突变将 101 位赖氨酸(K101)突变成丙氨酸(A),利用荧光共振能量转移(FRET)技术、耐盐生理测试和蛋白质活性检测进行详细探究。结果表明：突变后的 RDD 并未发生 FRET,说明 K101 并不影响 RDD 寡聚体形成；但相比于野生型 RDD,突变后的 RDD Na⁺/H⁺ 逆向转运活性下降 25.70%,证明 K101 是间接影响 Na⁺/H⁺ 逆向转运功能的残基。

关键词

RDD / 同源寡聚体 / Na+/H+ 逆向转运 / 定点突变

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基金资助

国家自然科学基金联合基金重点项目(U23A20143)

黑龙江省自然科学基金联合基金重点项目(ZL2024C001)