5ESC image
Deposition Date 2015-11-16
Release Date 2016-05-25
Last Version Date 2023-09-27
Entry Detail
PDB ID:
5ESC
Keywords:
Title:
Crystal structure of Group A Streptococcus HupZ
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.00 Å
R-Value Free:
0.20
R-Value Work:
0.16
R-Value Observed:
0.17
Space Group:
P 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:HupZ
Chain IDs:A, B, C, D
Chain Length:133
Number of Molecules:4
Biological Source:Streptococcus sp. 'group A'
Primary Citation
In vitro heme biotransformation by the HupZ enzyme from Group A streptococcus.
Biometals 29 593 609 (2016)
PMID: 27154580 DOI: 10.1007/s10534-016-9937-1

Abstact

In Group A streptococcus (GAS), the metallorepressor MtsR regulates iron homeostasis. Here we describe a new MtsR-repressed gene, which we named hupZ (heme utilization protein). A recombinant HupZ protein was purified bound to heme from Escherichia coli grown in the presence of 5-aminolevulinic acid and iron. HupZ specifically binds heme with stoichiometry of 1:1. The addition of NADPH to heme-bound HupZ (in the presence of cytochrome P450 reductase, NADPH-regeneration system and catalase) triggered progressive decrease of the HupZ Soret band and the appearance of an absorption peak at 660 nm that was resistance to hydrolytic conditions. No spectral changes were observed when ferredoxin and ferredoxin reductase were used as redox partners. Differential spectroscopy with myoglobin or with the ferrous chelator, ferrozine, confirmed that carbon monoxide and free iron are produced during the reaction. ApoHupZ was crystallized as a homodimer with a split β-barrel conformation in each monomer comprising six β strands and three α helices. This structure resembles the split β-barrel domain shared by the members of a recently described family of heme degrading enzymes. However, HupZ is smaller and lacks key residues found in the proteins of the latter group. Phylogenetic analysis places HupZ on a clade separated from those for previously described heme oxygenases. In summary, we have identified a new GAS enzyme-containing split β-barrel and capable of heme biotransformation in vitro; to the best of our knowledge, this is the first enzyme among Streptococcus species with such activity.

Legend

Protein

Chemical

Disease

Primary Citation of related structures