Crystal structure of Group A Streptococcus HupZ

Experimental Data Snapshot

  • Resolution: 2.00 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.167 
  • R-Value Observed: 0.171 

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In vitro heme biotransformation by the HupZ enzyme from Group A streptococcus.

Sachla, A.J.Ouattara, M.Romero, E.Agniswamy, J.Weber, I.T.Gadda, G.Eichenbaum, Z.

(2016) Biometals 29: 593-609

  • DOI: https://doi.org/10.1007/s10534-016-9937-1
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    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.

  • Organizational Affiliation

    Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA. zeichen@gsu.edu.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D
133Streptococcus sp. 'group AMutation(s): 0 
Find proteins for Q1JHG0 (Streptococcus pyogenes serotype M2 (strain MGAS10270))
Explore Q1JHG0 
Go to UniProtKB:  Q1JHG0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ1JHG0
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.00 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.167 
  • R-Value Observed: 0.171 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 41.823α = 78.59
b = 61.181β = 86.76
c = 61.347γ = 80.07
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2016-05-25
    Type: Initial release
  • Version 1.1: 2016-08-17
    Changes: Database references
  • Version 1.2: 2019-02-13
    Changes: Data collection, Derived calculations, Source and taxonomy
  • Version 1.3: 2023-09-27
    Changes: Data collection, Database references, Refinement description