7CXW

Structural insights into novel mechanisms of inhibition of the major b-carbonic anhydrase CafB from the pathogenic fungus Aspergillus fumigatus (C116 flipped form)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.176 

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Literature

Structural insights into novel mechanisms of inhibition of the major beta-carbonic anhydrase CafB from the pathogenic fungus Aspergillus fumigatus.

Kim, S.Yeon, J.Sung, J.Kim, N.J.Hong, S.Jin, M.S.

(2021) J Struct Biol 213: 107700-107700

  • DOI: https://doi.org/10.1016/j.jsb.2021.107700
  • Primary Citation of Related Structures:  
    7CXW, 7CXX, 7CXY

  • PubMed Abstract: 

    In fungi the β-class of carbonic anhydrases (β-CAs) are zinc metalloenzymes that are essential for growth, survival, differentiation, and virulence. Aspergillus fumigatus is the most important pathogen responsible for invasive aspergillosis and possesses two major β-CAs, CafA and CafB. Recently we reported the biochemical characterization and 1.8 Å crystal structure of CafA. Here, we report a crystallographic analysis of CafB revealing the mechanism of enzyme catalysis and establish the relationship of this enzyme to other β-CAs. While CafA has a typical open conformation, CafB, when exposed to acidic pH and/or an oxidative environment, has a novel type of active site in which a disulfide bond is formed between two zinc-ligating cysteines, expelling the zinc ion and stabilizing the inactive form of the enzyme. Based on the structural data, we generated an oxidation-resistant mutant (Y159A) of CafB. The crystal structure of the mutant under reducing conditions retains a catalytic zinc at the expected position, tetrahedrally coordinated by three residues (C57, H113 and C116) and an aspartic acid (D59), and replacing the zinc-bound water molecule in the closed form. Furthermore, the active site of CafB crystals grown under zinc-limiting conditions has a novel conformation in which the solvent-exposed catalytic cysteine (C116) is flipped out of the metal coordination sphere, facilitating release of the zinc ion. Taken together, our results suggest that A. fumigatus use sophisticated activity-inhibiting strategies to enhance its survival during infection.


  • Organizational Affiliation

    School of Life Sciences, GIST, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Carbonic anhydrase
A, B
228Aspergillus fumigatus Af293Mutation(s): 0 
Gene Names: AFUA_8G06550
EC: 4.2.1.1
UniProt
Find proteins for A4DA32 (Aspergillus fumigatus (strain ATCC MYA-4609 / CBS 101355 / FGSC A1100 / Af293))
Explore A4DA32 
Go to UniProtKB:  A4DA32
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA4DA32
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.176 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 118.812α = 90
b = 118.812β = 90
c = 68.074γ = 120
Software Package:
Software NamePurpose
HKL-2000data scaling
REFMACrefinement
PDB_EXTRACTdata extraction
HKL-2000data reduction
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Research Foundation (NRF, Korea)Korea, Republic OfNRF-2017M3A9F6029753
National Research Foundation (NRF, Korea)Korea, Republic OfNRF-2019M3E5D6063908

Revision History  (Full details and data files)

  • Version 1.0: 2021-03-31
    Type: Initial release
  • Version 1.1: 2023-11-29
    Changes: Data collection, Database references, Refinement description