1fwi: Difference between revisions
From Proteopedia
Jump to navigationJump to search
No edit summary |
No edit summary |
||
| Line 5: | Line 5: | ||
==Overview== | ==Overview== | ||
A mutant form of Klebsiella aerogenes urease possessing Ala instead of His, at position 134 (H134A) is inactive and binds approximately half the, normal complement of nickel (Park, I.-S., and Hausinger, R. P.(1993), Protein Sci. 2, 1034-1041). The crystal structure of the H134A protein was, obtained at 2.0-A resolution, and it confirms that only Ni-1 of the two, nickel ions found in the native enzyme is present. In contrast to the, pseudotetrahedral geometry observed for Ni-1 in native urease (where it is, liganded by His-246, His-272, one oxygen atom of carbamylated Lys-217, and, a water molecule at partial occupancy), the mononickel metallocenter in, the H134A protein was found to possess octahedral geometry and was, coordinated by the above protein ligands plus three water molecules. . | A mutant form of Klebsiella aerogenes urease possessing Ala instead of His, at position 134 (H134A) is inactive and binds approximately half the, normal complement of nickel (Park, I.-S., and Hausinger, R. P.(1993), Protein Sci. 2, 1034-1041). The crystal structure of the H134A protein was, obtained at 2.0-A resolution, and it confirms that only Ni-1 of the two, nickel ions found in the native enzyme is present. In contrast to the, pseudotetrahedral geometry observed for Ni-1 in native urease (where it is, liganded by His-246, His-272, one oxygen atom of carbamylated Lys-217, and, a water molecule at partial occupancy), the mononickel metallocenter in, the H134A protein was found to possess octahedral geometry and was, coordinated by the above protein ligands plus three water molecules. The, nickel site of H134A urease was probed by UV-visible, variable temperature, magnetic circular dichroism, and x-ray absorption spectroscopies. The, spectroscopic data are consistent with the presence of Ni(II) in, octahedral geometry coordinated by two histidylimidazoles and additional, oxygen and/or nitrogen donors. These data underscore the requirement of, Ni-2 for formation of active urease and demonstrate the important role of, Ni-2 in establishing the proper Ni-1 coordination geometry. | ||
==About this Structure== | ==About this Structure== | ||
1FWI is a | 1FWI is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Klebsiella_aerogenes Klebsiella aerogenes] with NI as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Urease Urease], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.1.5 3.5.1.5] Structure known Active Sites: ACT and NIL. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1FWI OCA]. | ||
==Reference== | ==Reference== | ||
| Line 22: | Line 22: | ||
[[Category: nickel metalloenzyme]] | [[Category: nickel metalloenzyme]] | ||
''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 14:45:30 2007'' | ||
