7KQ2

1.98 A resolution crystal structure of Group A Streptococcus H111A HupZ-V5-His6

Summary for 7KQ2

• Entry DOI: 10.2210/pdb7kq2/pdb
• Descriptor: HupZ, SULFATE ION, GLYCEROL, ... (4 entities in total)
• Functional Keywords: heme degradation, heme binding protein, enzyme, oxidoreductase
• Biological source: Streptococcus sp.
• Total number of polymer chains: 2
• Total formula weight: 37632.18

Authors

Traore, E.,Li, J.,Liu, A. (deposition date: 2020-11-13, release date: 2021-02-10, Last modification date: 2023-10-18)

Primary citation

Traore, E.S.,Li, J.,Chiura, T.,Geng, J.,Sachla, A.J.,Yoshimoto, F.,Eichenbaum, Z.,Davis, I.,Mak, P.J.,Liu, A.
Heme Binding to HupZ with a C-Terminal Tag from Group A Streptococcus.
Molecules, 26:-, 2021

PubMed Abstract: HupZ is an expected heme degrading enzyme in the heme acquisition and utilization pathway in Group A Streptococcus. The isolated HupZ protein containing a C-terminal V5-His tag exhibits a weak heme degradation activity. Here, we revisited and characterized the HupZ-V5-His protein via biochemical, mutagenesis, protein quaternary structure, UV-vis, EPR, and resonance Raman spectroscopies. The results show that the ferric heme-protein complex did not display an expected ferric EPR signal and that heme binding to HupZ triggered the formation of higher oligomeric states. We found that heme binding to HupZ was an O-dependent process. The single histidine residue in the HupZ sequence, His111, did not bind to the ferric heme, nor was it involved with the weak heme-degradation activity. Our results do not favor the heme oxygenase assignment because of the slow binding of heme and the newly discovered association of the weak heme degradation activity with the His-tag. Altogether, the data suggest that the protein binds heme by its His-tag, resulting in a heme-induced higher-order oligomeric structure and heme stacking. This work emphasizes the importance of considering exogenous tags when interpreting experimental observations during the study of heme utilization proteins.

PubMed: 33494451
DOI: 10.3390/molecules26030549

Experimental method

X-RAY DIFFRACTION (1.981 Å)