ホルモンオキシトシンと二価金属イオンとの相互作用

Thomas Wyttenbach¹, Dengfeng Liu, Michael T Bowers

¹Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, USA.

Journal of the American Chemical Society

|April 9, 2008

まとめ

オキシトシン (OT) は,酸性条件下で二価金属イオンを強く結合する. 基本的な条件下では,銅とニッケルがOTと複合体を形成し,特定の結合部位と生物学的影響を伴う構造変化を明らかにします.

科学分野:

バイオケミストリーバイオケミストリー
化学物理化学物理
コンピューティング・ケミストリー

背景:

オキシトシン (OT) は,循環性ノンアペプチドホルモンである.
二重金属イオン (X2+) は,生物系において極めて重要です.
金属-ペプチドの相互作用を理解することは,生物化学にとって不可欠です.

研究の目的:

オキシトシンの様々な二価金属イオンとの相互作用を調査する.
結合部位と形成された構造的複合体を明らかにする.
オキシトシンに対する金属イオン協調の生物学的影響を調査する.

主な方法:

質量スペクトロメトリー (MS) とイオン移動スペクトロメトリー (IMS).
分子動力学 (MD) と密度関数理論 (DFT) の計算.
衝突誘発解離 (CID) 実験.衝突誘発解離 (CID) 実験.

主要な成果:

オキシトシンは,酸性条件下で二価金属イオンに対する強い親和性を示します.
銅 (Cu2+) とニッケル (Ni2+) は,基本的な条件下で,OTと対陽性複合体を形成する.
構造分析は,特定の結合部位を持つ正方形平面,八面,または三角形二ピラミッド複合体を示唆しています.

結論:

二重金属イオンは,オキシトシンの構造と調整を大幅に変化させることができます.
結合部位と複雑な幾何学は,金属イオンタイプと溶液条件に依存する.
これらの構造の変化は,オキシトシンの生物学的機能に影響を及ぼす可能性があります.

さらに関連する動画

09:12

Assessing Cellular Stress and Inflammation in Discrete Oxytocin-secreting Brain Nuclei in the Neonatal Rat Before and After First Colostrum Feeding

Published on: November 14, 2018

11:38

Quantifying the Binding Interactions Between Cu(II) and Peptide Residues in the Presence and Absence of Chromophores

Published on: April 5, 2022

関連する概念動画

01:19

Complexation Equilibria: The Chelate Effect

In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...

02:51

Metal-Ligand Bonds

The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...

01:09

Complexation Equilibria: Factors Influencing Stability of Complexes

In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...

03:45

Formation of Complex Ions

A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...

01:26

EDTA: Auxiliary Complexing Reagents

EDTA titrations are usually carried out in highly basic conditions, where the fully deprotonated form of EDTA, Y4−, actively complexes with the free metal ions in the solution. Several metal ions precipitate as hydrous oxide (hydroxides, oxides, or oxyhydroxides) under these conditions, lowering the concentration of free metal ions in the solution. For this reason, auxiliary complexing agents or ligands such as ammonia, tartrate, citrate, or triethanolamine are used in EDTA titrations to...

01:22

EDTA: Chemistry and Properties

Polydentate ligands are most widely used in complexometric titrations because they form more stable complexes with the metal ions than mono- or bidentate ligands due to the chelate effect. Examples of polydentate ligands are ethylenediaminetetraacetic acid (EDTA), crown ethers, and cryptands. The most important feature of optimal polydentate ligands is the ability to form 1:1 complexes in a single-step process. Amino carboxylic acid derivatives are frequently used as complexing agents. EDTA is...

関連する実験動画