7BJ3

ScpA from Streptococcus pyogenes, S512A active site mutant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.209 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Enzyme kinetic and binding studies identify determinants of specificity for the immunomodulatory enzyme ScpA, a C5a inactivating bacterial protease.

Tecza, M.Kagawa, T.F.Jain, M.Cooney, J.C.

(2021) Comput Struct Biotechnol J 19: 2356-2365

  • DOI: https://doi.org/10.1016/j.csbj.2021.04.024
  • Primary Citation of Related Structures:  
    7BJ3

  • PubMed Abstract: 

    The Streptococcal C5a peptidase (ScpA) specifically inactivates the human complement factor hC5a, a potent anaphylatoxin recently identified as a therapeutic target for treatment of COVID-19 infections. Biologics used to modulate hC5a are predominantly monoclonal antibodies. Here we present data to support an alternative therapeutic approach based on the specific inactivation of hC5a by ScpA in studies using recombinant hC5a (rhC5a). Initial characterization of ScpA confirmed activity in human serum and against rhC5a desArg (rhC5a dR ), the predominant hC5a form in blood. A new FRET based enzyme assay showed that ScpA cleaved rhC5a at near physiological concentrations ( K m 185 nM). Surface Plasmon Resonance (SPR) and Isothermal Titration Calorimetry (ITC) studies established a high affinity ScpA-rhC5a interaction ( K D 34 nM, K D ITC 30.8 nM). SPR analyses also showed that substrate binding is dominated (88% of ΔG° bind ) by interactions with the bulky N-ter cleavage product (P N , 'core' residues 1-67) with interactions involving the C-ter R74 contributing most of the remaining ΔG° bind . Furthermore, reduced binding affinity following mutation of a subset of positively charged Arginine residues of P N and in the presence of higher salt concentrations, highlighted the importance of electrostatic interactions. These data provide the first in-depth study of the ScpA-C5a interaction and indicate that ScpA's ability to efficiently cleave physiological concentrations of C5a is driven by electrostatic interactions between an exosite on the enzyme and the 'core' of C5a. The results and methods described herein will facilitate engineering of ScpA to enhance its potential as a therapeutic for excessive immune response to infectious disease.


  • Organizational Affiliation

    Department of Chemical Sciences, University of Limerick, Limerick, Ireland.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
C5a peptidase1,002Streptococcus pyogenesMutation(s): 1 
Gene Names: scpA
EC: 3.4.21.110
UniProt
Find proteins for P58099 (Streptococcus pyogenes serotype M1)
Explore P58099 
Go to UniProtKB:  P58099
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP58099
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 5 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
EPE
Query on EPE

Download Ideal Coordinates CCD File 
D [auth A]4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID
C8 H18 N2 O4 S
JKMHFZQWWAIEOD-UHFFFAOYSA-N
MLA
Query on MLA

Download Ideal Coordinates CCD File 
E [auth A]MALONIC ACID
C3 H4 O4
OFOBLEOULBTSOW-UHFFFAOYSA-N
SO4
Query on SO4

Download Ideal Coordinates CCD File 
F [auth A]
G [auth A]
H [auth A]
I [auth A]
J [auth A]
F [auth A],
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth A],
L [auth A],
M [auth A],
N [auth A],
O [auth A],
P [auth A]
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
CA
Query on CA

Download Ideal Coordinates CCD File 
B [auth A]CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
NA
Query on NA

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C [auth A]SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.209 
  • Space Group: P 63 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 167.39α = 90
b = 167.39β = 90
c = 141.84γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
MOSFLMdata reduction
Aimlessdata scaling
PHASERphasing
Cootmodel building

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Irish Research CouncilIrelandRS/2005/222
Science Foundation IrelandIreland12/RC/2275_P2
Enterprise IrelandIrelandCF/2013/3336

Revision History  (Full details and data files)

  • Version 1.0: 2021-05-12
    Type: Initial release
  • Version 1.1: 2021-05-19
    Changes: Database references
  • Version 1.2: 2024-01-31
    Changes: Data collection, Database references, Refinement description