Structural highlights
Function
[ESTB_ASPFU] Displays specific TAFC esterase activity but does not hydrolyze fusarinine C, which has the same core structure as TAFC (PubMed:17586718). Hydrolysis optimizes but is not essential for TAFC-mediated iron uptake (PubMed:17586718).Both extra- and intracellular siderophores have been shown to be crucial for the virulence (PubMed:17586718). Subsequent to chelation of iron and uptake, FsC and TAFC are hydrolyzed and the iron is transferred to the metabolism or to the intracellular siderophore ferricrocin (FC) for transport and storage of iron (PubMed:17586718). Hydrolyzes both TAFC and DF-TAFC with equal efficiencies, suggesting that its function might not be restricted to the release of iron from the siderophore but might also include the degradation of the iron-free chelator to protect cells (PubMed:17586718).[1]
Publication Abstract from PubMed
Fungi utilize high-affinity chelators termed siderophores with chemically diverse structures to scavenge the essential nutrient iron from their surroundings. As they are among the strongest known Fe3+ binding agents, intracellular release of the heavy metal atom is facilitated by the activity of specific hydrolases. In this work, we report the characterization and x-ray structures of four siderophore esterases, AfEstB and AfSidJ from Aspergillus fumigatus, as well as AnEstB and AnEstA from Aspergillus nidulans. Even though they all display the conserved alpha/beta-hydrolase fold, we found remarkable structural and enzymatic discrepancies in their adaption to both related and chemically diverse substrates. A complex structure of AfEstB and its substrate triacetylfusarinine C gives insights into an active enzyme, with a tetrahedral coordination between the catalytic serine and the scissile ester bond.
Iron scavenging in Aspergillus species: Structural and biochemical insights into fungal siderophore esterases.,Ecker F, Haas H, Groll M, Huber E Angew Chem Int Ed Engl. 2018 Aug 1. doi: 10.1002/anie.201807093. PMID:30070018[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Kragl C, Schrettl M, Abt B, Sarg B, Lindner HH, Haas H. EstB-mediated hydrolysis of the siderophore triacetylfusarinine C optimizes iron uptake of Aspergillus fumigatus. Eukaryot Cell. 2007 Aug;6(8):1278-85. doi: 10.1128/EC.00066-07. Epub 2007 Jun 22. PMID:17586718 doi:http://dx.doi.org/10.1128/EC.00066-07
- ↑ Ecker F, Haas H, Groll M, Huber E. Iron scavenging in Aspergillus species: Structural and biochemical insights into fungal siderophore esterases. Angew Chem Int Ed Engl. 2018 Aug 1. doi: 10.1002/anie.201807093. PMID:30070018 doi:http://dx.doi.org/10.1002/anie.201807093
