概括
研究人员在酵母 (Saccharomyces cerevisiae) 中发现了一种类似于乌比奎丁的蛋白质,这对蛋白质降解至关重要. 这种蛋白质在真核生物中高度保存,这表明它具有基本的生物学作用.
科学领域:
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
- 生物化学 生物化学
背景情况:
- 乌比基是一种蛋白质,对细胞中选择性蛋白质降解至关重要.
- 乌比奎丁结合向蛋白质进行破坏.
- 乌比基可以自由存在,也可以附着在各种细胞蛋白中.
研究的目的:
- 为了研究酵母 (Saccharomyces cerevisiae) 中的乌比奎丁的存在和功能.
- 描述酵母菌的基因组织和蛋白质序列.
- 为了比较酵母基因与其在更高的真核生物中的对应物.
主要方法:
- 对Saccharomyces cerevisiae ubiquitin基因进行隔离和测序.
- 对酵母提取物的分析,以检测基的结合活性.
- 酵母乌比奎氨基酸序列与人类乌比奎的比较.
主要成果:
- 在酵母中发现了一种同类于人类泛素的蛋白质.
- 酵母提取物证明了人类无素与内源蛋白质的ATP依赖的结合.
- 酵母基因包含六个连续的,从头到尾的重复,编码相同的氨基酸序列.
- 酵母菌的乌比奎丁在76个残留物中仅有3个不同于高等真核生物中的乌比奎丁.
结论:
- 酵母布基因因是由加工含有多个布基因重复的前体蛋白质生成的.
- 乌比基是已知最保存的蛋白质之一,突出其基本的细胞功能.
- 这些发现证实了ubiquitin在不同真核生物物种中蛋白质降解中的保留作用.
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In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
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In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a cap to the 5' end of the growing transcript. In this process, a 5' phosphate is replaced by modified guanosine that has a methyl group attached (7-methyl guanosine). This 5' cap helps the cell...
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a cap to the 5' end of the growing transcript. In this process, a 5' phosphate is replaced by modified guanosine that has a methyl group attached (7-methyl guanosine). This 5' cap helps the cell...
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In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin...
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