NUCLEOLIN, THE MAJOR NUCLEOLAR PROTEIN OF GROWING EUKARYOTIC CELLS - AN UNUSUAL PROTEIN-STRUCTURE REVEALED BY THE NUCLEOTIDE-SEQUENCE
NUCLEOLIN, THE MAJOR NUCLEOLAR PROTEIN OF GROWING EUKARYOTIC CELLS - AN UNUSUAL PROTEIN-STRUCTURE REVEALED BY THE NUCLEOTIDE-SEQUENCE
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DOI：
10.1073/pnas.84.6.1472
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发表时间：
1987-03-01
影响因子：
11.1
通讯作者：
AMALRIC, F
中科院分区：
文献类型：
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作者：
LAPEYRE, B;BOURBON, H;AMALRIC, F
核仁蛋白（也称为 C23）是指数生长的真核细胞的主要核仁蛋白。发现它与核仁内染色质和前核糖体颗粒有关。通过使用多克隆抗血清，从在表达载体λgt11中构建的中国仓鼠卵巢细胞文库分离核仁素cDNA克隆。分离的cDNA编码含有核仁素713个氨基酸中的679个残基的多肽。氨基酸序列呈现出几个不寻常的特征：特别是在分子的两端发现了重复序列。在 NH2 末端近端部分发现了六次重复，Hy-Thr-Pro-Hy-Lys-Lys-Hy-Hy，其中 Hy 是非极性残基，随后是包含 25、25 和 33 个谷氨酸或天冬氨酸残基的三个酸性片段。在此区域还观察到四个潜在的磷酸化位点（丝氨酸）。该蛋白质的 COOH 末端近端部分带有富含甘氨酸的区域，其中苯丙氨酸和二甲基精氨酸残基相当规则地散布。分子的两个末端部分表现出独特的潜在二级结构：α-螺旋（NH2末端）和延伸（COOH末端）。中心区域表现出交替的疏水性和亲水性伸展。检测到五个潜在的 N 糖基化位点。该蛋白质的结构可能反映了前核糖体生物合成中的两个功能：与染色质（NH2 末端）和前核糖体（COOH 末端）的相互作用。
Nucleolin (also called C23) is the major nucleolar protein of exponentially growing eukaryotic cells. It is found associated with intranucleolar chromatin and preribosomal particles. Through use of a polyclonal antiserum, nucleolin cDNA clones were isolated from a Chinese hamster ovary cell library constructed in the expression vector .lambda.gt11. The isolated cDNAs encoded a polypeptide containing 679 residues of the 713 amino acids of nucleolin. The amino acid sequence presents several unusual features: in particular, repetitive sequences are found at both ends of the molecule. A repeat, Hy-Thr-Pro-Hy-Lys-Lys-Hy-Hy, in which Hy is a non-polar residue, is found six times in the NH2-end proximal portion, followed by three acidic stretches containing 25, 25, and 33 glutamic acid or aspartic acid residues. Four potential phosphorylation sites (serines) are also observed in this region. The COOH-terminal proximal portion of the protein carries a glycine-rich region with fairly regularly interspersed phenylalanine and dimethylarginine residues. The two terminal portions of the molecule exhibit unique potential secondary structures: .alpha.-helix (NH2 terminus) and extended (COOH terminus). The central region exhibits alternating hydrophobic and hydrophilic stretches. Five potential N glycosylation sites are detected. The structure of this protein may reflect two functions in preribosome biogenesis: interaction with chromatin (NH2 terminus) and with preribosomes (COOH terminus).