ハプトグロービン-ヘモグロビン複合体の構造
Christian Brix Folsted Andersen1, Morten Torvund-Jensen, Marianne Jensby Nielsen
1Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark. cbfa@biokemi.au.dk
Nature
|August 28, 2012
まとめ
ハプトグロビンは,血液溶解中に有害なフリーヘモグロビンを捕獲し,中和させます. 結晶構造は,ハプトグロービンがヘモグロビンと結合し,組織を酸化的損傷から保護し,CD163受容体経由でクリアランスを促進する方法を明らかにします.
科学分野:
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
- 免疫学 免疫学とは
背景:
- 赤血球のヘモグロビンは酸素輸送に不可欠ですが,血液溶解中に血に放出されると組織に損傷を与える可能性があります.
- ハプトグロービンは,自由ヘモグロビンを結合し,保護複合体を形成する急性相タンパク質です.
- マラリアやヘモグロビノパシーに見られる血管内溶解は,ヘモグロビン-ハプトグロビン相互作用を理解する必要があります.
研究 の 目的:
- 豚の二次元ハプトグロービン-ヘモグロビン複合体の結晶構造を決定する.
- ヘモグロビン誘発の損傷に対するハプトグロービンの保護的役割の分子メカニズムを解明する.
- ハプトグロービン-ヘモグロビン複合体とスキャベンジャー受容体CD163.3の相互作用を調査する.
主な方法:
- 複合体の構造を決定するために2.9 Åの解像度のX線結晶学.
- 小角X線散射 (SAXS) により,CD163.3との相互作用を研究した.
- タンパク質-タンパク質のインターフェースと残留物のアクセシビリティの分析.
主要な成果:
- 結晶構造は,ハプトグロービン二分化におけるベータ鎖の交換による新しい融合CCPドメイン構造を明らかにしています.
- ハプトグロビンは,ヘモグロビンのアルファおよびベータサブユニットの両方と広範に相互作用し,緊密な結合を説明します.
- 酸化的ダメージに敏感な重要なヘモグロビン残基は,ハプトグロービン-ヘモグロビン界面内でシールドされています.
- 特定のハプトグロービンループはCD163受容体への結合を促進し,二重複合体は潜在的に2つの受容体を結合します.
結論:
- この構造は,ハプトグロービンによるヘモグロビン中和の原子レベルの洞察を提供し,その保護機能を強調しています.
- ハプトグロービンのメカニズムは,反応性ヘモグロビン部位を直接遮断し,受容体媒介クリアランスを促進することを含む.
- この発見は,CD163に対するマルチメリックハプトグロービン-ヘモグロビンの強化された親和性を説明し,ヘム毒性の除去に不可欠である.
関連する概念動画
Protein and Protein Structure
71.5K
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...
A protein's shape is critical to its function. For example, an enzyme...
71.5K
Gene Families
8.0K
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...
8.0K
Protein Complex Assembly
12.5K
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...
12.5K
Conjugated Proteins
21.1K
Simple proteins and protein complexes contain only amino acids. In contrast, many other proteins, called conjugated proteins, covalently bond with non-protein moieties.
Nucleoproteins are protein complexes that contain nucleic acids, categorized as deoxyribonucleoproteins (DNPs) or ribonucleoproteins (RNPs) respectively. The nucleosome is a typical example of a DNP where nuclear DNA is associated with histone proteins. The major antigen for the Covid-19 virus SARS-CoV is an RNP that is critical...
Nucleoproteins are protein complexes that contain nucleic acids, categorized as deoxyribonucleoproteins (DNPs) or ribonucleoproteins (RNPs) respectively. The nucleosome is a typical example of a DNP where nuclear DNA is associated with histone proteins. The major antigen for the Covid-19 virus SARS-CoV is an RNP that is critical...
21.1K
Globular Proteins
8.0K
In organisms, proteins are the most abundant macromolecules. They act as the building blocks of life and play various crucial roles in the body. Proteins can be broadly classified into two distinct subtypes based on their shape and solubilities: globular proteins and fibrous proteins.
Globular proteins serve many important physiological functions, such as acting as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be soluble in the aqueous...
Globular proteins serve many important physiological functions, such as acting as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be soluble in the aqueous...
8.0K
Hemoglobin
8.8K
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...
8.8K


