Structure and mechanism of copper–carbonic anhydrase II: a nitrite reductase
Nitric oxide (NO) promotes vasodilation through the activation of guanylate cyclase, resulting in the relaxation of the smooth muscle vasculature and a subsequent decrease in blood pressure. Therefore, its regulation is of interest for the treatment and prevention of heart disease. An example is pul...
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| Format: | Article |
| Language: | English |
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International Union of Crystallography
2020-03-01
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| Series: | IUCrJ |
| Subjects: | |
| Online Access: | http://scripts.iucr.org/cgi-bin/paper?S2052252520000986 |
| _version_ | 1798031109992218624 |
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| author | Jacob T. Andring Chae Un Kim Robert McKenna |
| author_facet | Jacob T. Andring Chae Un Kim Robert McKenna |
| author_sort | Jacob T. Andring |
| collection | DOAJ |
| description | Nitric oxide (NO) promotes vasodilation through the activation of guanylate cyclase, resulting in the relaxation of the smooth muscle vasculature and a subsequent decrease in blood pressure. Therefore, its regulation is of interest for the treatment and prevention of heart disease. An example is pulmonary hypertension which is treated by targeting this NO/vasodilation pathway. In bacteria, plants and fungi, nitrite (NO2−) is utilized as a source of NO through enzymes known as nitrite reductases. These enzymes reduce NO2− to NO through a catalytic metal ion, often copper. Recently, several studies have shown nitrite reductase activity of mammalian carbonic anhydrase II (CAII), yet the molecular basis for this activity is unknown. Here we report the crystal structure of copper-bound human CAII (Cu–CAII) in complex with NO2− at 1.2 Å resolution. The structure exhibits Type 1 (T-1) and 2 (T-2) copper centers, analogous to bacterial nitrite reductases, both required for catalysis. The copper-substituted CAII active site is penta-coordinated with a `side-on' bound NO2−, resembling a T-2 center. At the N terminus, several residues that are normally disordered form a porphyrin ring-like configuration surrounding a second copper, acting as a T-1 center. A structural comparison with both apo- (without metal) and zinc-bound CAII (Zn–CAII) provides a mechanistic picture of how, in the presence of copper, CAII, with minimal conformational changes, can function as a nitrite reductase. |
| first_indexed | 2024-04-11T19:50:58Z |
| format | Article |
| id | doaj.art-04aacaf857ad4494bc62c39ee6da2d24 |
| institution | Directory Open Access Journal |
| issn | 2052-2525 |
| language | English |
| last_indexed | 2024-04-11T19:50:58Z |
| publishDate | 2020-03-01 |
| publisher | International Union of Crystallography |
| record_format | Article |
| series | IUCrJ |
| spelling | doaj.art-04aacaf857ad4494bc62c39ee6da2d242022-12-22T04:06:17ZengInternational Union of CrystallographyIUCrJ2052-25252020-03-017228729310.1107/S2052252520000986lz5032Structure and mechanism of copper–carbonic anhydrase II: a nitrite reductaseJacob T. Andring0Chae Un Kim1Robert McKenna2Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610 USADepartment of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of KoreaDepartment of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610 USANitric oxide (NO) promotes vasodilation through the activation of guanylate cyclase, resulting in the relaxation of the smooth muscle vasculature and a subsequent decrease in blood pressure. Therefore, its regulation is of interest for the treatment and prevention of heart disease. An example is pulmonary hypertension which is treated by targeting this NO/vasodilation pathway. In bacteria, plants and fungi, nitrite (NO2−) is utilized as a source of NO through enzymes known as nitrite reductases. These enzymes reduce NO2− to NO through a catalytic metal ion, often copper. Recently, several studies have shown nitrite reductase activity of mammalian carbonic anhydrase II (CAII), yet the molecular basis for this activity is unknown. Here we report the crystal structure of copper-bound human CAII (Cu–CAII) in complex with NO2− at 1.2 Å resolution. The structure exhibits Type 1 (T-1) and 2 (T-2) copper centers, analogous to bacterial nitrite reductases, both required for catalysis. The copper-substituted CAII active site is penta-coordinated with a `side-on' bound NO2−, resembling a T-2 center. At the N terminus, several residues that are normally disordered form a porphyrin ring-like configuration surrounding a second copper, acting as a T-1 center. A structural comparison with both apo- (without metal) and zinc-bound CAII (Zn–CAII) provides a mechanistic picture of how, in the presence of copper, CAII, with minimal conformational changes, can function as a nitrite reductase.http://scripts.iucr.org/cgi-bin/paper?S2052252520000986catalytic metal ionscopper–carbonic anhydrase iiapo-carbonic anhydrase iinitrite reductasesnitric oxidex-ray crystallography |
| spellingShingle | Jacob T. Andring Chae Un Kim Robert McKenna Structure and mechanism of copper–carbonic anhydrase II: a nitrite reductase IUCrJ catalytic metal ions copper–carbonic anhydrase ii apo-carbonic anhydrase ii nitrite reductases nitric oxide x-ray crystallography |
| title | Structure and mechanism of copper–carbonic anhydrase II: a nitrite reductase |
| title_full | Structure and mechanism of copper–carbonic anhydrase II: a nitrite reductase |
| title_fullStr | Structure and mechanism of copper–carbonic anhydrase II: a nitrite reductase |
| title_full_unstemmed | Structure and mechanism of copper–carbonic anhydrase II: a nitrite reductase |
| title_short | Structure and mechanism of copper–carbonic anhydrase II: a nitrite reductase |
| title_sort | structure and mechanism of copper carbonic anhydrase ii a nitrite reductase |
| topic | catalytic metal ions copper–carbonic anhydrase ii apo-carbonic anhydrase ii nitrite reductases nitric oxide x-ray crystallography |
| url | http://scripts.iucr.org/cgi-bin/paper?S2052252520000986 |
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