5WI6

Human beta-1 tryptase mutant Ile99Cys


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.72 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.193 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Dual functionality of beta-tryptase protomers as both proteases and cofactors in the active tetramer.

Maun, H.R.Liu, P.S.Franke, Y.Eigenbrot, C.Forrest, W.F.Schwartz, L.B.Lazarus, R.A.

(2018) J. Biol. Chem. 293: 9614-9628

  • DOI: 10.1074/jbc.M117.812016

  • PubMed Abstract: 
  • Human β-tryptase, a tetrameric trypsin-like serine protease, is an important mediator of the allergic inflammatory responses in asthma. During acute hypersensitivity reactions, mast cells degranulate, releasing active tetramer as a complex with prote ...

    Human β-tryptase, a tetrameric trypsin-like serine protease, is an important mediator of the allergic inflammatory responses in asthma. During acute hypersensitivity reactions, mast cells degranulate, releasing active tetramer as a complex with proteoglycans. Extensive efforts have focused on developing therapeutic β-tryptase inhibitors, but its unique activation mechanism is less well explored. Tryptase is active only after proteolytic removal of the pro-domain followed by tetramer formation via two distinct symmetry-related interfaces. We show that the cleaved I16G mutant cannot tetramerize, likely due to impaired insertion of its N-terminus into its 'activation pocket', indicating allosteric linkage at multiple sites on each protomer. We engineered cysteines into each of the two distinct interfaces (Y75C for small or I99C for large) to assess the activity of each tetramer and disulfide-locked dimer. Using size-exclusion chromatography and enzymatic assays, we demonstrate that the two large tetramer interfaces regulate enzymatic activity, elucidating the importance of this protein-protein interaction for allosteric regulation. Notably, the I99C large interface dimer is active, even in the absence of heparin. We show that a monomeric β-tryptase mutant (I99C*:Y75A:Y37bA where C* is cysteinylated Cys99) cannot form a dimer or tetramer, yet is active, but only in the presence of heparin. Thus heparin both stabilizes the tetramer and allosterically conditions the active site. We hypothesize that each β-tryptase protomer in the tetramer has two distinct roles, acting both as a protease and as a cofactor for its neighboring protomer, to allosterically regulate enzymatic activity, providing a rationale for direct correlation of tetramer stability with proteolytic activity.


    Organizational Affiliation

    Genentech, Inc., United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Tryptase alpha/beta-1
A, B, C, D
245Homo sapiensMutation(s): 1 
Gene Names: TPSAB1 (TPS1, TPS2, TPSB1)
EC: 3.4.21.59
Find proteins for Q15661 (Homo sapiens)
Go to Gene View: TPSAB1
Go to UniProtKB:  Q15661
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, B, C, D
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
0GJ
Query on 0GJ

Download SDF File 
Download CCD File 
A, B, C, D
L-alpha-glutamyl-N-{(1S)-4-{[amino(iminio)methyl]amino}-1-[(1S)-2-chloro-1-hydroxyethyl]butyl}glycinamide
C14 H28 Cl N6 O5
XELWNHKFCNMWQO-LPEHRKFASA-O
 Ligand Interaction
Biologically Interesting Molecules 1 Unique
IDChainsNameType/Class2D Diagram3D Interactions
PRD_000288 (0GJ)
Query on PRD_000288
A,B,C,DGLU-GLY-ARG-CHLOROMETHYL KETONEPeptide-like / Inhibitor

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Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.72 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.193 
  • Space Group: P 32 2 1
Unit Cell:
Length (Å)Angle (°)
a = 96.743α = 90.00
b = 96.743β = 90.00
c = 238.553γ = 120.00
Software Package:
Software NamePurpose
BUSTERrefinement
PHASERphasing
Aimlessdata scaling
XDSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2018-04-25
    Type: Initial release
  • Version 1.1: 2018-05-02
    Type: Data collection, Database references
  • Version 1.2: 2018-05-16
    Type: Data collection, Structure summary
  • Version 1.3: 2018-07-04
    Type: Data collection, Database references