2OHA

Myoglobin cavity mutant F138W

2OHA の概要

• エントリーDOI: 10.2210/pdb2oha/pdb
• 関連するPDBエントリー: 2OH8 2OH9 2OHB
• 分子名称: Myoglobin, SULFATE ION, PROTOPORPHYRIN IX CONTAINING FE, ... (4 entities in total)
• 機能のキーワード: myoglobin, ligand entry and exit pathways, oxygen storage-transport complex, oxygen storage/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: 18212.81

構造登録者

Phillips Jr., G.N.,Soman, J.,Olson, J.S. (登録日: 2007-01-09, 公開日: 2007-01-23, 最終更新日: 2023-12-27)

主引用文献

Olson, J.S.,Soman, J.,Phillips, G.N.
Ligand pathways in myoglobin: A review of trp cavity mutations.
Iubmb Life, 59:552-562, 2007

PubMed Abstract: The pathways for ligand entry and exit in myoglobin have now been well established by a wide variety of experimental results, including pico- to nano- to microsecond transient absorbance measurements and time-resolved X-ray crystallographic measurements. Trp insertions have been used to block, one at a time, the three major cavities occupied by photodissociated ligands. In this work, we review the effects of the L29(B10)W mutation, which places a large indole ring in the initial 'docking site' for photodissociated ligands. Then, the effects of blocking the Xe4 site with I28W, V68W, and I107W mutations and the Xe1 cavity with L89W, L104W, and F138W mutations are described. The structures of four of these mutants are shown for the first time (Trp28, Trp68, Trp107, and Trp 138 sperm whale metMb). All available results support a 'side path' mechanism in which ligands move into and out of myoglobin by outward rotation of the HisE7 side chain, but after entry can migrate into internal cavities, including the distal Xe4 and proximal Xe1 binding sites. The distal cavities act like the pocket of a baseball glove, catching the ligand and holding it long enough for the histidine gate to close and facilitate internal coordination with the heme iron atom. The physiological role of the proximal Xe1 site is less clear because changes in the size of this cavity have minimal effects on overall O(2) binding parameters.

PubMed: 17701550
DOI: 10.1080/15216540701230495

実験手法

X-RAY DIFFRACTION (1.8 Å)