A conserved motif in the yeast nucleolar protein Nop2p contains an essential cysteine residue
A conserved motif in the yeast nucleolar protein Nop2p contains an essential cysteine residue
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DOI：
10.1042/0264-6021:3370029
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发表时间：
1999-01-01
影响因子：
4.1
通讯作者：
Redman, KL
中科院分区：
文献类型：
--
作者：
King, M;Ton, D;Redman, KL
Nop 2 p是酿酒酵母中一种重要的核仁蛋白，参与核糖体大亚基的组装。它与人p120有很大的同源性，p120是一种在许多人类癌症中过表达的增殖相关核仁抗原。在Nop 2 p、p120和细菌Fmu蛋白中发现含有不变的Pro-Cys二肽的基序。共9个保守的残基，包括Pro（423）和Cys（424），在Nop 2 p中通过定点突变被单独改变。通过将Cys（424）转化为丙氨酸或丝氨酸来消除Nop 2 p功能。所有其他Nop 2 p突变都测试了持续的酵母活力，包括Pro（423）的甘氨酸取代和第二个保守的半胱氨酸转化为丙氨酸。Cys（424）在Nop 2 p中的关键作用是有趣的，这是由于与脯氨酸相邻的半胱氨酸残基在许多核苷酸修饰酶中具有关键作用。
Nop2p is an essential nucleolar protein in Saccharomyces cerevisiae that is involved in large ribosomal subunit assembly. It has substantial homology with human p120, the proliferation-associated nucleolar antigen that is overexpressed in many human cancers. A motif containing an invariant Pro-Cys dipeptide is found in Nop2p, p120 and the bacterial Fmu proteins. A total of nine conserved residues, including Pro(423) and Cys(424), were individually altered in Nop2p by site-directed mutagenesis. Nop2p function was abolished by conversion of Cys(424) into either alanine or serine. All of the other Nop2p mutations tested sustained yeast viability, including glycine replacement of Pro(423) and the conversion of a second conserved cysteine into alanine. The crucial role of Cys(424) in Nop2p is intriguing, due to the critical roles that cysteine residues adjacent to a proline have in a number of nucleotide-modifying enzymes.