2iwk
From Proteopedia
| Line 5: | Line 5: | ||
==Overview== | ==Overview== | ||
| - | The difficult chemistry of nitrous oxide (N2O) reduction to gaseous, nitrogen (N2) in biology is catalysed by the novel micro4-sulphide-bridged, tetranuclear Cuz cluster of the N2O reductases (N2OR). Two, spectroscopically distinct forms of this cluster have been identified as, CuZ and CuZ*. We have obtained a 1.86 A resolution crystal structure of, the pink-purple species of N2OR from Achromobacter cycloclastes (AcN2OR), isolated under aerobic conditions. This structure reveals a previously, unobserved ligation with two oxygen atoms from H2O/OH- coordinated to Cu1, and Cu4 of the catalytic centre. We ascribe this structure to be that of, the CuZ form of the cluster, since the previously reported structures of, two blue species of N2ORs, also isolated aerobically, have characterised, the ... | + | The difficult chemistry of nitrous oxide (N2O) reduction to gaseous, nitrogen (N2) in biology is catalysed by the novel micro4-sulphide-bridged, tetranuclear Cuz cluster of the N2O reductases (N2OR). Two, spectroscopically distinct forms of this cluster have been identified as, CuZ and CuZ*. We have obtained a 1.86 A resolution crystal structure of, the pink-purple species of N2OR from Achromobacter cycloclastes (AcN2OR), isolated under aerobic conditions. This structure reveals a previously, unobserved ligation with two oxygen atoms from H2O/OH- coordinated to Cu1, and Cu4 of the catalytic centre. We ascribe this structure to be that of, the CuZ form of the cluster, since the previously reported structures of, two blue species of N2ORs, also isolated aerobically, have characterised, the redox inactive CuZ* form, revealing a single water molecule at Cu4., Exposure of the as-isolated AcN2OR to sodium iodide led to reduction of, the electron-donating CuA site and the formation of a blue species., Structure determination of this adduct at 1.7 A resolution showed that, iodide was bound at the CuZ site bridging the Cu1 and Cu4 ions. This, structure represents the first observation of an inhibitor bound to the, Cu1-Cu4 edge of the catalytic cluster, providing clear evidence for this, being the catalytic edge in N2ORs. These structures, together with the, published structural and spectroscopic data, give fresh insight into the, mode of substrate binding, reduction and catalysis. |
==About this Structure== | ==About this Structure== | ||
| - | 2IWK is a | + | 2IWK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Achromobacter_cycloclastes Achromobacter cycloclastes] with CU, IOD, CA, CL, NA and S as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Nitrous-oxide_reductase Nitrous-oxide reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.7.99.6 1.7.99.6] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2IWK OCA]. |
==Reference== | ==Reference== | ||
| Line 36: | Line 36: | ||
[[Category: periplasmic electron gating]] | [[Category: periplasmic electron gating]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 13:23:42 2007'' |
Revision as of 11:18, 5 November 2007
|
INHIBITOR-BOUND FORM OF NITROUS OXIDE REDUCTASE FROM ACHROMOBACTER CYCLOCLASTES AT 1.7 ANGSTROM RESOLUTION
Overview
The difficult chemistry of nitrous oxide (N2O) reduction to gaseous, nitrogen (N2) in biology is catalysed by the novel micro4-sulphide-bridged, tetranuclear Cuz cluster of the N2O reductases (N2OR). Two, spectroscopically distinct forms of this cluster have been identified as, CuZ and CuZ*. We have obtained a 1.86 A resolution crystal structure of, the pink-purple species of N2OR from Achromobacter cycloclastes (AcN2OR), isolated under aerobic conditions. This structure reveals a previously, unobserved ligation with two oxygen atoms from H2O/OH- coordinated to Cu1, and Cu4 of the catalytic centre. We ascribe this structure to be that of, the CuZ form of the cluster, since the previously reported structures of, two blue species of N2ORs, also isolated aerobically, have characterised, the redox inactive CuZ* form, revealing a single water molecule at Cu4., Exposure of the as-isolated AcN2OR to sodium iodide led to reduction of, the electron-donating CuA site and the formation of a blue species., Structure determination of this adduct at 1.7 A resolution showed that, iodide was bound at the CuZ site bridging the Cu1 and Cu4 ions. This, structure represents the first observation of an inhibitor bound to the, Cu1-Cu4 edge of the catalytic cluster, providing clear evidence for this, being the catalytic edge in N2ORs. These structures, together with the, published structural and spectroscopic data, give fresh insight into the, mode of substrate binding, reduction and catalysis.
About this Structure
2IWK is a Single protein structure of sequence from Achromobacter cycloclastes with CU, IOD, CA, CL, NA and S as ligands. Active as Nitrous-oxide reductase, with EC number 1.7.99.6 Structure known Active Site: AC1. Full crystallographic information is available from OCA.
Reference
Insight into catalysis of nitrous oxide reductase from high-resolution structures of resting and inhibitor-bound enzyme from Achromobacter cycloclastes., Paraskevopoulos K, Antonyuk SV, Sawers RG, Eady RR, Hasnain SS, J Mol Biol. 2006 Sep 8;362(1):55-65. Epub 2006 Jul 12. PMID:16904686
Page seeded by OCA on Mon Nov 5 13:23:42 2007
Categories: Achromobacter cycloclastes | Nitrous-oxide reductase | Single protein | Antonyuk, S.V. | Eady, R.R. | Hasnain, S.S. | Paraskevopoulos, K. | Sawers, R.G. | CA | CL | CU | IOD | NA | S | Calcium | Catalysis | Copper | Copper chemistry | Denitrification | Metal-binding | Nitrous oxide binding | Oxidoreductase | Periplasmic electron gating
