6WIA

CRYSTAL STRUCTURE OF HUMAN PROTECTIVE PROTEIN/CATHEPSIN A, DFP-INHIBITED (AGED)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.21 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.196 

wwPDB Validation   3D Report Full Report



Literature

Structural and kinetic evidence of aging after organophosphate inhibition of human Cathepsin A.

Bouknight, K.D.Jurkouich, K.M.Compton, J.R.Khavrutskii, I.V.Guelta, M.A.Harvey, S.P.Legler, P.M.

(2020) Biochem Pharmacol 177: 113980-113980

  • DOI: 10.1016/j.bcp.2020.113980
  • Primary Citation of Related Structures:  
    6WIA

  • PubMed Abstract: 
  • Human Cathepsin A (CatA) is a lysosomal serine carboxypeptidase of the renin-angiotensin system (RAS) and is structurally similar to acetylcholinesterase (AChE). CatA can remove the C-terminal amino acids of endothelin I, angiotensin I, Substance P, oxyt ...

    Human Cathepsin A (CatA) is a lysosomal serine carboxypeptidase of the renin-angiotensin system (RAS) and is structurally similar to acetylcholinesterase (AChE). CatA can remove the C-terminal amino acids of endothelin I, angiotensin I, Substance P, oxytocin, and bradykinin, and can deamidate neurokinin A. Proteomic studies identified CatA and its homologue, SCPEP1, as potential targets of organophosphates (OP). CatA could be stably inhibited by low µM to high nM concentrations of racemic sarin (GB), soman (GD), cyclosarin (GF), VX, and VR within minutes to hours at pH 7. Cyclosarin was the most potent with a kinetically measured dissociation constant (K I ) of 2 µM followed by VR (K I  = 2.8 µM). Bimolecular rate constants for inhibition by cyclosarin and VR were 1.3 × 10 3 M -1 sec -1 and 1.2 × 10 3 M -1 sec -1 , respectively, and were approximately 3-orders of magnitude lower than those of human AChE indicating slower reactivity. Notably, both AChE and CatA bound diisopropylfluorophosphate (DFP) comparably and had K I DFP  = 13 µM and 11 µM, respectively. At low pH, greater than 85% of the enzyme spontaneously reactivated after OP inhibition, conditions under which OP-adducts of cholinesterases irreversibly age. At pH 6.5 CatA remained stably inhibited by GB and GF and <10% of the enzyme spontaneously reactivated after 200 h. A crystal structure of DFP-inhibited CatA was determined and contained an aged adduct. Similar to AChE, CatA appears to have a "backdoor" for product release. CatA has not been shown previously to age. These results may have implications for: OP-associated inflammation; cardiovascular effects; and the dysregulation of RAS enzymes by OP.


    Organizational Affiliation

    U.S. Naval Research Laboratory, 4555 Overlook Ave., Washington, DC 20375, United States. Electronic address: patricia.legler@nrl.navy.mil.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Lysosomal protective protein A458Homo sapiensMutation(s): 0 
Gene Names: CTSAPPGB
EC: 3.4.16.5
Find proteins for P10619 (Homo sapiens)
Explore P10619 
Go to UniProtKB:  P10619
NIH Common Fund Data Resources
PHAROS:  P10619
Protein Feature View
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  • Reference Sequence
Oligosaccharides

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Entity ID: 2
MoleculeChainsChain Length2D Diagram Glycosylation3D Interactions
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
B, C
2 N-Glycosylation Oligosaccharides Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.21 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.196 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 91.273α = 90
b = 101.999β = 101.61
c = 48.114γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
PDB_EXTRACTdata extraction
APEXdata reduction
APEXdata scaling
PHASERphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Department of Defense (DOD, United States)United States#GW150096

Revision History 

  • Version 1.0: 2020-04-29
    Type: Initial release
  • Version 1.1: 2020-05-20
    Changes: Database references
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Structure summary