新型ヒスティジン-ヘム共性結合が,ヘモグロビンで示されている
B Christie Vu1, A Daniel Jones, Juliette T J Lecomte
1Department of Chemistry and the Center for Biomolecular Structure and Function, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Journal of the American Chemical Society
|July 18, 2002
まとめ
Synechocystisのヘモグロビンは,ヘムを含む化学反応を通じて,そのポリペプチド鎖にヘム結合をします.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- タンパク質化学 タンパク質化学
背景:
- Synechocystis sp. のリコンビナントヘモグロビンから. PCC 6803は,ヘムタンパク質の相互作用を研究するためのモデルシステムです.
- 血球蛋白へのヘム結合は,ヘモグロビン機能に不可欠ですが,正確な化学的メカニズムは完全に理解されていません.
研究 の 目的:
- Synechocystisのヘモグロビンへのヘム結合の化学的メカニズムを解明する.
- ヘムとタンパク質の両方の特定の反応群を特定する.
主な方法:
- 核磁共振 (NMR) スペクトロスコーピ (1H,ホモ核,1H-15N)
- ペプシンダイジェストの質量スペクトロメトリー (MS)
- ディチオニットと改変したポルフィリンを用いた化学改変の研究.
主要な成果:
- ニュートラルなpHでディチオナイトを投与すると,シネコシスティスのヘモグロビンにヘムが素早く結合する.
- ヘムの2ビニル群が反応部分として識別された.
- 質量スペクトロメトリーにより,C端の12メルペプチドへの結合部位が特定されました.
- NMRは,ヒスティジン117 (His117) を改変された残留物として特定し,イミダゾール環のネプシロンがヘムのビニルカルファと反応した.
- 改変は Zn プロトポルフィリンIXでは発生せず,ヘム鉄の減少が不可欠であることを示しています.
結論:
- この研究は,グロービンへのヘム結合のための新しい化学的経路を明らかにしている.
- この反応は,ヒスティジンの残基がヘムのビニル群によって直接変化し,ディチオニット誘発による還元によって促進される.
- 研究結果は,翻訳後の改変とヘムタンパク質のクロスリンクメカニズムについての洞察を提供します.
さらに関連する動画
18:27One-step Purification of Twin-Strep-tagged Proteins and Their Complexes on Strep-Tactin Resin Cross-linked With Bis(sulfosuccinimidyl) Suberate (BS3)
Published on: April 20, 2014
09:06Efficient and Site-specific Antibody Labeling by Strain-promoted Azide-alkyne Cycloaddition
Published on: December 23, 2016
関連する概念動画
02:43Peptide Bonds
A peptide bond covalently attaches amino acids through a dehydration reaction. One amino acid's carboxyl group and another amino acid's amino group combine, releasing a water molecule. The resulting bond is the peptide bond. The products that such linkages form are peptides. As more amino acids join this growing chain, the resulting chain is a polypeptide. Each polypeptide has a free amino group at one end. This end has the N-terminal, or the amino-terminal, and the other end has a free...
01:57Gene Families
Gene families consist of groups of genes proposed to have originated from a common ancestor. Typically these arise through events in which a gene or genes are mistakenly duplicated during cell division. Unlike their parent genes (which are subject to selection pressure to maintain function), these gene copies do not need to preserve their sequences and may evolve at a relatively faster rate.
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
02:21Globular and Fibrous Proteins
Many proteins can be classified into two distinct subtypes - globular or fibrous. These two types differ in their shapes and solubilities.
Globular proteins are also known as spheroproteins and typically are approximately round in shape. They contain a mix of amino acid types and contain differing sequences in their primary structures. Globular proteins have many different functions, such as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be...
Globular proteins are also known as spheroproteins and typically are approximately round in shape. They contain a mix of amino acid types and contain differing sequences in their primary structures. Globular proteins have many different functions, such as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be...
01:41The Supercomplexes in the Crista Membrane
The mitochondrial cristae membrane is the primary site for the oxidative phosphorylation (OXPHOS) process of energy conversion mediated through respiratory complexes I to V. These complexes have been widely studied for decades, and it has been proven that they form supramolecular structures called respiratory supercomplexes (SC). These higher-order complexes may be crucial in maintaining the biochemical structure and improving the physiological activity of the individual complexes while...
01:25Fibronectins Connect Cells with ECM
Fibronectin is an adhesive glycoprotein present in the extracellular matrix of embryogenic and adult tissue. These molecules primarily aid in regulating cell motility and attachment. A fibronectin molecule is composed of two identical polypeptide chains attached to each other by a pair of disulfide bonds at the C-terminal.
Both proteoglycans and collagen are attached to fibronectin proteins, which, in turn, are attached to integrin proteins. These integrin proteins interact with transmembrane...
Both proteoglycans and collagen are attached to fibronectin proteins, which, in turn, are attached to integrin proteins. These integrin proteins interact with transmembrane...
01:24Hemoglobin
Hemoglobin is a globular protein made up of four subunits. Two of these subunits are alpha chains, and the other two are beta chains. Each subunit contains a molecule of heme, which has an iron atom and can bind to oxygen. When an oxygen molecule binds to one heme group, it changes the shape of hemoglobin, making it easier for the other heme groups to bind oxygen as well.
When all four heme groups are bound to oxygen, the resulting molecule is called oxyhemoglobin. As a result, arterial blood...
When all four heme groups are bound to oxygen, the resulting molecule is called oxyhemoglobin. As a result, arterial blood...