title: Paramagnetic NMR investigations of Co(II) and Ni(II) amicyanin.
abstract: The paramagnetic 1H NMR spectra of the Co(II) and Ni(II) substituted forms of the type 1 blue copper protein (cupredoxin) amicyanin have been assigned. This is the first such analysis of a cupredoxin, which has a distorted tetrahedral active site with the ligands provided by two histidines, a cysteine and a methionine. The isotropic shifts of the resonances in these spectra are compared with those of Co(II) and Ni(II) azurin. A number of interesting similarities and differences are found. The coordination of the metal by the two equatorial histidine ligands is very similar in both proteins. The interaction between the introduced metal and the thiolate sulfur of the equatorial cysteine ligand is enhanced in the amicyanin derivatives. Resonances belonging to the weak axial methionine ligand exhibit much larger shifts in the amicyanin derivatives, indicative of shorter M(II)-S(Met) distances. The presence of shorter axial M(II)-S(Met) and equatorial M(II)-S(Cys) distances in both Co(II) and Ni(II) amicyanin is ascribed to the absence of a second axially interacting amino acid at the active site of this cupredoxin.
authors.affiliation: Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Salgado
authors.forename: A P
authors.initials: AP
authors.lastname: Kalverda
authors.forename: R E
authors.initials: RE
authors.lastname: Diederix
authors.forename: G W
authors.initials: GW
authors.lastname: Canters
authors.forename: J M
authors.initials: JM
authors.lastname: Moratal
authors.forename: A T
authors.initials: AT
authors.lastname: Lawler
authors.forename: C
authors.initials: C
authors.lastname: Dennison
mesh_terms: D001400:Azurin / Q000031:analogs & derivatives* / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D003035:Cobalt / Q000737:chemistry* / Q000378:metabolism; D003300:Copper / Q000737:chemistry / Q000378:metabolism; D006639:Histidine; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008715:Methionine / Q000737:chemistry; D009532:Nickel / Q000737:chemistry* / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001426:Bacterial Proteins; D008024:Ligands; C050107:cupredoxin; C017079:mauC protein, Methylobacterium extorquens; D001400:Azurin; D003035:Cobalt; D006639:Histidine; D003300:Copper; D009532:Nickel; D008715:Methionine