相关实验视频
Updated: Jul 26, 2026

07:59
Folding and Characterization of a Bio-responsive Robot from DNA Origami
Published on: December 3, 2015
一个新的UAG编码的残留物在甲基甲基转移酶的结构中
Bing Hao1, Weimin Gong, Tsuneo K Ferguson
1Department of Biochemistry, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
概括
甲基胺甲基转移酶使用独特的珀色子 (UAG) 进行翻译. 研究人员发现,这种UAG编码子在Methanosarcina barkeri MtmB酶中编码了一种新型氨基酸l-pyrrolysine.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 微生物学 微生物学
背景情况:
- 甲原甲基胺甲基转移酶的基因含有内框架珀 (UAG) 编码子.
- 这种编码子通常是停止信号,但在这些基因的翻译过程中会被阅读.
研究的目的:
- 为了确定甲原甲基胺甲基转移酶中UAG码子编码的氨基酸的身份.
- 为了阐明Methanosarcina barkeri. 的MtmB酶的结构.
主要方法:
- 使用X射线晶体学来确定MtmB的1.55安格斯特罗姆分辨率结构.
- 对电子密度图进行分析,以确定UAG编码的残留物.
主要成果:
- 结构显示MtmB是一个同质体,子单元具有TIM桶折叠.
- 用UAG编码的残留物的电子密度与21种标准氨基酸不同.
- 该残留物与氨酸与 (4R,5R) -4-替代-氨酸-5-碳酸盐的氨酸结合一致.
结论:
- 一种新型的氨基酸,暂时命名为l-pyrrolysine,由甲基甲基胺甲基转移酶中的珀 (UAG) 码子编码.
- 这一发现扩大了已知的遗传密码和蛋白质合成中使用的氨基酸谱.
相关概念视频
The ADP/ATP Carrier Protein
ADP/ATP carrier or AAC protein is the most abundant carrier protein in the inner mitochondrial membrane. It transports large quantities of ADP and ATP, equivalent to the average human body weight, every day. Among other transporters, ACC protein is one of the best-studied members of the mitochondrial carrier protein family. The ADP/ATP carrier protein comprises two transmembrane helices connected to a loop and a single alpha-helix on the matrix side. It switches between two conformational...
Protein Folding Quality Check in the RER
ER is the primary site for the maturation and folding of soluble and transmembrane secretory proteins. The calnexin cycle is a specific chaperone system that folds and assesses the confirmation of N-glycosylated proteins before they can exit the ER lumen. The primary players of this quality check pipeline are the lectins, ER-resident chaperones, and a glucosyl transferase enzyme. In case the calnexin system in the lumen fails to salvage a misfolded protein, it is transported to the cytoplasm...
Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Proteoglycans
Glycans, a class of complex heterogeneous molecules, can be covalently attached to proteins to form glycosylated proteins that regulate various physiological and pathological processes. Glycosylated proteins or glycoproteins comprise N-linked and O-linked oligosaccharides. O-glycosylation is the most common type of protein glycosylation. Here, glycans attach to the oxygen atom of the hydroxyl groups of Serine or Threonine residues. O-linked glycosylation occurs later in protein processing,...
Nucleic Acids and Nucleotides
Nucleic acids are the most important macromolecules for the continuity of life. They carry the cell's genetic blueprint and have instructions for its functioning. The two main types of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
Deoxyribonucleic Acid (DNA)
DNA is the genetic material in all living organisms, ranging from single-celled bacteria to multicellular mammals. It is in the nucleus of eukaryotes and the organelles such as chloroplasts and mitochondria. In...
Deoxyribonucleic Acid (DNA)
DNA is the genetic material in all living organisms, ranging from single-celled bacteria to multicellular mammals. It is in the nucleus of eukaryotes and the organelles such as chloroplasts and mitochondria. In...
Nucleic Acid Structure
The pentose sugar in DNA is deoxyribose, while in RNA the pentose sugar is ribose. The difference between the sugars is the presence of the hydroxyl group on the ribose's second carbon and a hydrogen on the deoxyribose's second carbon. The phosphate residue attaches to the hydroxyl group of the 5′ carbon of one sugar and the hydroxyl group of the 3′ carbon of the sugar of the next nucleotide, which forms a 5′ to 3′ phosphodiester linkage.
DNA Structure
DNA has a double-helix structure. The...
DNA Structure
DNA has a double-helix structure. The...

