PDBsum entry 7cxy

Lyase

PDB id: 7cxy

Contents

Protein chains

214 a.a.

Metals

_ZN ×2

Waters ×136

PDB id:

7cxy

Name:

Lyase

Title:

Structural insights into novel mechanisms of inhibition of the major b-carbonic anhydrase cafb from the pathogenic fungus aspergillus fumigatus (zinc-bound form)

Structure:

Carbonic anhydrase. Chain: a, b. Synonym: carbonate dehydratase. Engineered: yes. Mutation: yes

Source:

Neosartorya fumigata (strain atcc mya-4609 / af293 / cbs 101355 / fgsc a1100). Organism_taxid: 330879. Strain: atcc mya-4609 / af293 / cbs 101355 / fgsc a1100. Gene: afua_8g06550. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.20Å R-factor: 0.186 R-free: 0.229

Authors:

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

Key ref:

S.Kim et al. (2021). Structural insights into novel mechanisms of inhibition of the major β-carbonic anhydrase CafB from the pathogenic fungus Aspergillus fumigatus. J Struct Biol, 213, 107700. PubMed id: 33545350 DOI: 10.1016/j.jsb.2021.107700

Date:

02-Sep-20 Release date: 31-Mar-21

Protein chains

A4DA32  (A4DA32_ASPFU) -  Carbonic anhydrase from Aspergillus fumigatus (strain ATCC MYA-4609 / CBS 101355 / FGSC A1100 / Af293)

Seq: 228 a.a.

Struc: 214 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.4.2.1.1 - carbonic anhydrase.
• Reaction: hydrogencarbonate + H⁺ = CO2 + H2O
• Cofactor: Zn(2+)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Added reference

DOI no: 10.1016/j.jsb.2021.107700

J Struct Biol 213:107700 (2021)

PubMed id: 33545350

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

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

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.