3M38

The roles of Glutamates and Metal ions in a rationally designed nitric oxide reductase based on myoglobin: I107E FeBMb (No metal ion binding to FeB site)

3M38 の概要

• エントリーDOI: 10.2210/pdb3m38/pdb
• 関連するPDBエントリー: 3M39 3M3A 3M3B
• 分子名称: Myoglobin, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• 機能のキーワード: alpha helix, heme protein, metal-binding, no reductase, oxygen transport
• 由来する生物種: Physeter catodon (Sperm whale)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 17913.34

構造登録者

Lin, Y.-W.,Yeung, N.,Gao, Y.-G.,Miner, K.D.,Tian, S.,Robinson, H.,Lu, Y. (登録日: 2010-03-08, 公開日: 2010-05-12, 最終更新日: 2024-02-21)

主引用文献

Lin, Y.W.,Yeung, N.,Gao, Y.G.,Miner, K.D.,Tian, S.,Robinson, H.,Lu, Y.
Roles of glutamates and metal ions in a rationally designed nitric oxide reductase based on myoglobin.
Proc.Natl.Acad.Sci.USA, 107:8581-8586, 2010

PubMed Abstract: A structural and functional model of bacterial nitric oxide reductase (NOR) has been designed by introducing two glutamates (Glu) and three histidines (His) in sperm whale myoglobin. X-ray structural data indicate that the three His and one Glu (V68E) residues bind iron, mimicking the putative Fe(B) site in NOR, while the second Glu (I107E) interacts with a water molecule and forms a hydrogen bonding network in the designed protein. Unlike the first Glu (V68E), which lowered the heme reduction potential by approximately 110 mV, the second Glu has little effect on the heme potential, suggesting that the negatively charged Glu has a different role in redox tuning. More importantly, introducing the second Glu resulted in a approximately 100% increase in NOR activity, suggesting the importance of a hydrogen bonding network in facilitating proton delivery during NOR reactivity. In addition, EPR and X-ray structural studies indicate that the designed protein binds iron, copper, or zinc in the Fe(B) site, each with different effects on the structures and NOR activities, suggesting that both redox activity and an intermediate five-coordinate heme-NO species are important for high NOR activity. The designed protein offers an excellent model for NOR and demonstrates the power of using designed proteins as a simpler and more well-defined system to address important chemical and biological issues.

PubMed: 20421510
DOI: 10.1073/pnas.1000526107

実験手法

X-RAY DIFFRACTION (1.42 Å)