30Sリボソームサブユニットに結合したイニシアーション因子の結晶構造
A P Carter1, W M Clemons, D E Brodersen
1Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
まとめ
結晶構造は,イニシアーション因子IF1が30Sリボソームサブユニットに結合し,Aサイトをブロックし,正確なタンパク質合成のためにその構成を変更する方法を示しています.
科学分野:
- 分子生物学は分子生物学である.
- 構造生物学 構造生物学とは
- バイオケミストリー バイオケミストリー
背景:
- 精密なタンパク質合成は,正確な翻訳開始に依存しています.
- プロカリオットのトランスレーション開始には,開始因子IF1,IF2,IF3が含まれる.
- 30Sリボソームサブユニットは,翻訳開始において重要な役割を果たします.
研究 の 目的:
- 始動因子IF1と30Sリボソームサブユニットとの複合体の結晶構造を決定する.
- IF1が30Sサブユニット構成に影響を与える分子メカニズムを解明する.
- IF1結合がリボソームA部位にどのように影響するかを理解する.
主な方法:
- X線結晶学を用いて,IF1-30Sリボソームサブユニット複合体の構造を得ました.
- 構造分析は,IF1と30Sサブユニット,特にAサイトでの相互作用に焦点を当てました.
主要な成果:
- 結晶構造はIF1が30Sサブユニットと結合し,リボソームA部位を遮断していることを示している.
- IF1結合により,16SRNAのヘリックス44の機能的に重要な塩基 (A1492,A1493) が外転する.
- これらの塩基はIF1内のポケットに隔離され,H44と30Sサブユニット領域の長距離構造変化を誘導します.
結論:
- この構造は,IF1がA部位で結合することで,30Sサブユニットにおける全身構造の変化が誘発される方法の分子説明を提供する.
- このメカニズムは,プロカリオットにおける正確な翻訳開始を確保するために極めて重要です.
- この発見は,タンパク質合成中のリボソーム機能の調節に関する洞察を提供します.
さらに関連する動画
14:55Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
09:15Combining X-Ray Crystallography with Small Angle X-Ray Scattering to Model Unstructured Regions of Nsa1 from S. Cerevisiae
Published on: January 10, 2018
関連する概念動画
Protein and Protein Structure
Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective. They may serve in transport, storage, or membranes; or they may be toxins or enzymes. Their structures, like their functions, vary greatly. They are all, however, amino acid polymers arranged in a linear sequence.
A protein's shape is critical to its function. For example, an enzyme can...
A protein's shape is critical to its function. For example, an enzyme can...
Protein Complex Assembly
Proteins can form homomeric complexes with another unit of the same protein or heteromeric complexes with different types. Most protein complexes self-assemble spontaneously via ordered pathways, while some proteins need assembly factors that guide their proper assembly. Despite the crowded intracellular environment, proteins usually interact with their correct partners and form functional complexes.
Many viruses self-assemble into a fully functional unit using the infected host cell to...
Many viruses self-assemble into a fully functional unit using the infected host cell to...
tRNA Activation
Aminoacyl-tRNA synthetases are present in both eukaryotes and bacteria. Though eukaryotes have 20 different aminoacyl-tRNA synthetases to couple to 20 amino acids, many bacteria do not have genes for all of these aminoacyl-tRNA synthetases. Despite this, they still use all 20 amino acids to synthesize their proteins. For instance, some bacteria do not have the gene encoding the enzyme that couples glutamine with its partner tRNA. In these organisms, one enzyme adds glutamic acid to all of the...
tRNA Activation
Aminoacyl-tRNA synthetases are present in both eukaryotes and bacteria. Though eukaryotes have 20 different aminoacyl-tRNA synthetases to couple to 20 amino acids, many bacteria do not have genes for all of these aminoacyl-tRNA synthetases. Despite this, they still use all 20 amino acids to synthesize their proteins. For instance, some bacteria do not have the gene encoding the enzyme that couples glutamine with its partner tRNA. In these organisms, one enzyme adds glutamic acid to all of the...
Initiation of Translation
Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
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...
