کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1178048 962660 2016 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Molecular oxygen migration through the xenon docking sites of human hemoglobin in the R-state
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Molecular oxygen migration through the xenon docking sites of human hemoglobin in the R-state
چکیده انگلیسی


• Xe binding to hemoglobin decreases the efficiency of O2 escape from the α subunits.
• Two path model for ligand migration in the hemoglobin subunits was introduced.
• Two-third escaping molecules of O2 leave the α subunits via Xe docking sites.

A nanosecond laser flash-photolysis technique was used to study bimolecular and geminate molecular oxygen (O2) rebinding to tetrameric human hemoglobin and its isolated α and β chains in buffer solutions equilibrated with 1 atm of air and up to 25 atm of xenon. Xenon binding to the isolated α chains and to the α subunits within tetrameric hemoglobin was found to cause a decrease in the efficiency of O2 escape by a factor of ~ 1.30 and 3.3, respectively. A kinetic model for O2 dissociation, rebinding, and migration through two alternative pathways in the hemoglobin subunits was introduced and discussed. It was shown that, in the isolated α chains and α subunits within tetrameric hemoglobin, nearly one- and two-third escaping molecules of O2 leave the protein via xenon docking sites, respectively. The present experimental data support the idea that O2 molecule escapes from the β subunits mainly through the His(E7) gate, and show unambiguously that, in the α subunits, in addition to the direct E7 channel, there is at least one alternative escape route leading to the exterior via the xenon docking sites.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics - Volume 1864, Issue 9, September 2016, Pages 1110–1121
نویسندگان
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