MyJournals Home  

RSS FeedsDynamic and structural differences between heme oxygenase-1 and -2 are due to differences in their C-terminal regions [Enzymology] (Journal of Biological Chemistry)

 
 

17 may 2019 10:01:42

 
Dynamic and structural differences between heme oxygenase-1 and -2 are due to differences in their C-terminal regions [Enzymology] (Journal of Biological Chemistry)
 




Heme oxygenase (HO) catalyzes heme degradation, a process crucial for regulating cellular levels of this vital, but cytotoxic, cofactor. Two HO isoforms, HO1 and HO2, exhibit similar catalytic mechanisms and efficiencies. They also share catalytic core structures, including the heme-binding site. Outside their catalytic cores are two regions unique to HO2: a 20-amino acid-long N-terminal extension and a C-terminal domain containing two heme regulatory motifs (HRMs) that bind heme independently of the core. Both HO isoforms contain a C-terminal hydrophobic membrane anchor; however, their sequences diverge. Here, using hydrogen-deuterium exchange MS, size-exclusion chromatography, and sedimentation velocity, we investigated how these divergent regions impact the dynamics and structure of the apo and heme-bound forms of HO1 and HO2. Our results reveal that heme binding to the catalytic cores of HO1 and HO2 causes similar dynamic and structural changes in regions (proximal, distal, and A6 helices) within and linked to the heme pocket. We observed that full-length HO2 is more dynamic than truncated forms lacking the membrane-anchoring region, despite sharing the same steady-state activity and heme-binding properties. In contrast, the membrane anchor of HO1 did not influence its dynamics. Furthermore, although residues within the HRM domain facilitated HO2 dimerization, neither the HRM region nor the N-terminal extension appeared to affect HO2 dynamics. In description, our results highlight significant dynamic and structural differences between HO2 and HO1 and indicate that their dissimilar C-terminal regions play a major role in controlling the structural dynamics of these two proteins.


Del.icio.us Digg Facebook Google StumbleUpon Twitter
 
33 viewsCategory: Biochemistry
 
Indomethacin impairs mitochondrial dynamics by activating the PKC{zeta}-p38-DRP1 pathway and inducing apoptosis in gastric cancer and normal mucosal cells [Cell Biology] (Journal of Biological Chemistry)
Functional complementation reveals that 9 of the 13 human V-ATPase subunits can functionally substitute for their yeast orthologs [Cell Biology] (Journal of Biological Chemistry)
 
 
blog comments powered by Disqus


MyJournals.org
The latest issues of all your favorite science journals on one page

Username:
Password:

Register | Retrieve

Search:

Biochemistry

Use these buttons to bookmark us:
Del.icio.us Digg Facebook Google StumbleUpon Twitter


Valid HTML 4.01 Transitional
Copyright © 2008 - 2019 Indigonet Services B.V.. Contact: Tim Hulsen. Read here our privacy notice.
Other websites of Indigonet Services B.V.: Nieuws Vacatures News Tweets Travel Photos Nachrichten Indigonet Finances Leer Mandarijn