{"entry": {"accession": "MF7000858", "general": {"name": "CafB, C116 flipped form (Aspergillus fumigatus)", "pdb_id": "7cxw", "exp_method": "X-ray", "resolution": "2.20", "assembly": "Homodimer", "source_organism": "Aspergillus fumigatus", "publication": {"pmid": "33545350", "authors": "Kim S, Yeon J, Sung J, Kim NJ, Hong S, Jin MS", "title": "Structural insights into novel mechanisms of inhibition of the major \u03b2-carbonic anhydrase CafB from the pathogenic fungus Aspergillus fumigatus.", "journal": "J. Struct. Biol.", "year": "2021", "issue": "1", "volume": "213", "pages": "107700", "abstract": "In fungi the \u03b2-class of carbonic anhydrases (\u03b2-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 \u03b2-CAs, CafA and CafB. Recently we reported the biochemical characterization and 1.8\u00a0\u00c5 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 \u03b2-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."}}, "function": {"molecular_function": {"go": [{"accession": "GO:0004089", "name": "carbonate dehydratase activity"}, {"accession": "GO:0008270", "name": "zinc ion binding"}]}, "cellular_component": {"go": {"accession": "GO:0005737", "name": "cytoplasm"}}, "biological_process": {"go": [{"accession": "GO:0015976", "name": "carbon utilization"}, {"accession": "GO:0071244", "name": "cellular response to carbon dioxide"}, {"accession": "GO:0034599", "name": "cellular response to oxidative stress"}]}}, "macromolecules": {"general": {"nr_of_chains": "2", "nr_of_unique_protein_segments": "1", "class": "Homooligomeric enzymes", "subclass": "Homodimeric enzymes", "note": "All chains according to the most probable oligomerization state stored in PDBe were considered."}, "chain": [{"id": "A", "name": "Carbonic anhydrase", "source_organism": "Aspergillus fumigatus", "uniprot": {"id": "A4DA32", "start": "10", "end": "225", "coverage": "94%", "sequence": "MEPSDQKVDTVPQYLKQSHERIFENNRAWVATKMKDDPAFFEKLSAGQTPEYLYIGCSDSRVPANEIMGLEAGEVFVHRNIANLVPNTDLNVMSVINYAVRHLQVKHIVVCGHYHCGGVKAALTPSDLGLLNPWLRNVRDVYRLHEQELDGIQDATARYRRLVELNVIESCRNVIKTAAVQQSFHERQFPVVHGWIFDVETGLLRDLEIDFEETLRDIKKIYNLAPGS", "length": "228"}, "regions": {"region": [{"region_type": "secondary structure", "region_name": "helix", "region_start": "12", "region_end": "37"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "39", "region_end": "45"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "63", "region_end": "68"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "71", "region_end": "73"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "81", "region_end": "84"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "89", "region_end": "102"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "117", "region_end": "123"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "128", "region_end": "130"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "131", "region_end": "145"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "145", "region_end": "151"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "154", "region_end": "176"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "177", "region_end": "188"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "210", "region_end": "220"}, {"region_type": "secondary structure", "region_name": "strand", "region_start": "52", "region_end": "57"}, {"region_type": "secondary structure", "region_name": "strand", "region_start": "75", "region_end": "80"}, {"region_type": "secondary structure", "region_name": "strand", "region_start": "107", "region_end": "112"}, {"region_type": "secondary structure", "region_name": "strand", "region_start": "191", "region_end": "197"}, {"region_type": "secondary structure", "region_name": "strand", "region_start": "204", "region_end": "206"}, {"region_type": "pfam", "region_id": "PF00484", "region_name": "Carbonic anhydrase", "region_start": "52", "region_end": "203"}]}}, {"id": "B", "name": "Carbonic anhydrase", "source_organism": "Aspergillus fumigatus", "uniprot": {"id": "A4DA32", "start": "10", "end": "225", "coverage": "94%", "sequence": "MEPSDQKVDTVPQYLKQSHERIFENNRAWVATKMKDDPAFFEKLSAGQTPEYLYIGCSDSRVPANEIMGLEAGEVFVHRNIANLVPNTDLNVMSVINYAVRHLQVKHIVVCGHYHCGGVKAALTPSDLGLLNPWLRNVRDVYRLHEQELDGIQDATARYRRLVELNVIESCRNVIKTAAVQQSFHERQFPVVHGWIFDVETGLLRDLEIDFEETLRDIKKIYNLAPGS", "length": "228"}, "regions": {"region": [{"region_type": "secondary structure", "region_name": "helix", "region_start": "12", "region_end": "37"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "39", "region_end": "47"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "63", "region_end": "68"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "71", "region_end": "73"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "81", "region_end": "84"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "89", "region_end": "102"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "117", "region_end": "123"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "128", "region_end": "130"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "131", "region_end": "151"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "154", "region_end": "176"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "177", "region_end": "188"}, {"region_type": "secondary structure", "region_name": "helix", "region_start": "210", "region_end": "220"}, {"region_type": "secondary structure", "region_name": "strand", "region_start": "52", "region_end": "57"}, {"region_type": "secondary structure", "region_name": "strand", "region_start": "75", "region_end": "80"}, {"region_type": "secondary structure", "region_name": "strand", "region_start": "107", "region_end": "113"}, {"region_type": "secondary structure", "region_name": "strand", "region_start": "191", "region_end": "197"}, {"region_type": "secondary structure", "region_name": "strand", "region_start": "204", "region_end": "206"}, {"region_type": "pfam", "region_id": "PF00484", "region_name": "Carbonic anhydrase", "region_start": "52", "region_end": "203"}]}}]}, "evidence": {"evidence_level": "Indirect evidence", "evidence_coverage": "The full structure participates in mutual synergistic folding.", "sequence_domain": "Carbonic anhydrase", "complex_evidence": "The native carbonic anhydrase is dimeric in solution, in agreement with being a tightly associated dimer with a large, hydrophobic buried surface area. The extended \u03b2-sheet core consisting of ten \u03b2\u2013strands is equally contributed by the two monomers, and the N-terminal helix of each monomer extends around the other monomer. Based on the highly intertwined structure, the monomeric form is most probably not a stable, independently folding unit. The two active sites are also located in clefts at the dimeric interface, further suggesting that dimer is the functional form (PMID:32515610).", "chain_evidence": [{"chain_id": "A", "support": "N/A"}, {"chain_id": "B", "support": "N/A"}]}, "related_structures": {"id": ["MF7000278", "MF7000279", "MF7000856", "MF7000857", "MF7000858", "MF7000859"]}}}