Cyclisation of Lys48-linked diubiquitin in vitro and in vivo
Cyclisation of Lys48-linked diubiquitin in vitro and in vivo
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Lys48 连接的双泛素的体外和体内环化
DOI：
10.1016/j.febslet.2012.10.011
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发表时间：
2012
期刊：
影响因子：
3.5
通讯作者：
Sokratous K
中科院分区：
文献类型：
--
作者：
Sokratous K
泛素(Ub)能够通过其7个赖氨酸(Lys)残基中的任何一个与相邻Ub单体的C末端缩合而形成聚合的异肽连接链。商业体外产生的Lys48连接的二聚体(Lys48-UB2)的电喷雾电离质谱仪(ESI-MS)显示了主要的环状二聚体。通过不能结合USP5/异肽酶-T的锌指泛素结合域(ZnF-UBP)，证实了该群体中没有游离的C末端。从骨骼肌和培养的哺乳动物细胞中纯化的内源性Ub2被发现含有环状Lys48-Ub2，表明在体内也可以发生多聚Ub的环化。
Ubiquitin (Ub) is able to form polymeric isopeptide-linked chains through condensation of any of its seven lysine (Lys) residues with the C-terminus of an adjacent Ub monomer. Electrospray ionisation mass spectrometry (ESI-MS) of commercial in vitro-generated Lys48-linked di-Ub (Lys48-Ub2) revealed a major population of cyclised dimer. The absence of a free C-terminus in this population was confirmed by an inability to bind the zinc finger ubiquitin-binding domain (ZnF-UBP) of USP5/isopeptidase-T. Endogenous Ub2purified from skeletal muscle and cultured mammalian cells was found to contain cyclic Lys48-Ub2, demonstrating that cyclisation of poly-Ub can also occur in vivo.