Issue 5, 2018

Tertiary dynamics of human adult hemoglobin fixed in R and T quaternary structures

Abstract

Protein dynamics of human adult hemoglobin and its mutants restricted in R and T quaternary states following ligand photolysis were studied by time-resolved resonance Raman spectroscopy. In the time-resolved spectra, we observed spectral changes of in-plane stretching modes of heme and the iron–histidine stretching mode of the Fe–His bond for all the hemoglobin samples. The βD99N mutant, which adopts the R state in both the ligand-bound and the deoxy forms, showed similar temporal behaviors in time-resolved resonance Raman spectra as wild-type recombinant hemoglobin until 10 μs, consistent with the fact that the mutant undergoes only the tertiary structural changes in the R state. The βN102T mutant, which adopts the T state in both the ligand-bound and the deoxy forms, showed much slower tertiary structural changes, suggesting that the EF helical motion is decelerated by the change of the intersubunit interactions. The present data indicate that the allosteric kinetic response between the interhelical hydrogen bonds of the EF helices and the intersubunit hydrogen bonds is bidirectional. The implications of these results for understanding the allosteric pathway of Hb are discussed in detail.

Graphical abstract: Tertiary dynamics of human adult hemoglobin fixed in R and T quaternary structures

Supplementary files

Article information

Article type
Paper
Submitted
14 Sept. 2017
Accepted
11 Dec. 2017
First published
11 Dec. 2017

Phys. Chem. Chem. Phys., 2018,20, 3363-3372

Tertiary dynamics of human adult hemoglobin fixed in R and T quaternary structures

S. Chang, M. Mizuno, H. Ishikawa and Y. Mizutani, Phys. Chem. Chem. Phys., 2018, 20, 3363 DOI: 10.1039/C7CP06287G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements