title: Two inhibition targets by [Cr(2gb)(3)](3+) and [Co(2gb)(3)](3+) on redox enzymes of spinach thylakoids.
abstract: [Cr(2gb)(3)]Cl(ZnCl(4)), [Cr(2gb)(3)]Cl(3), and [Co(2gb)(3)]Cl(3) were synthesized and characterized. Their chemical structures and the oxidation states of their metal centers remained unchanged in solution. The effects of these compounds, CrCl(3) and [Co(NH(3))(6)]Cl(3), on photosynthesis were investigated. The coordination compounds inhibit ATP synthesis and electron flow (basal, phosphorylating, and uncoupled), behaving as Hill reaction inhibitors. The target for [Cr(2gb)(3)]Cl(ZnCl(4)) is located at the Q(B) level. In contrast, the interaction sites of [Cr(2gb)(3)]Cl(3) and [Co(2gb)(3)]Cl(3) are located in the span from P(680) to Q(A) and at the b(6)f complex. Neither CrCl(3) nor [Co(NH(3))(6)]Cl(3) inhibited photosynthesis. The 100% inhibition on PS II of [Cr(2gb)(3)]Cl(ZnCl(4)) is explained in terms of a synergystic effect between the 2gb-chromium(III) coordination compound and the ZnCl(4)(2)(-) anion.
authors.affiliation: Departamento de Química Inorgánica, Universidad Nacional Autónoma de México.
authors.forename: A E
authors.initials: AE
authors.lastname: Ceniceros-Gómez
authors.forename: B
authors.initials: B
authors.lastname: King-Díaz
authors.forename: N
authors.initials: N
authors.lastname: Barba-Behrens
authors.forename: B
authors.initials: B
authors.lastname: Lotina-Hennsen
authors.forename: S E
authors.initials: SE
authors.lastname: Castillo-Blum
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D001562:Benzimidazoles / Q000494:pharmacology*; D004579:Electron Transport / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D009942:Organometallic Compounds / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010788:Photosynthesis / Q000187:drug effects*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000187:drug effects; D018515:Plant Leaves / Q000378:metabolism; D018724:Spinacia oleracea / Q000378:metabolism*; D020524:Thylakoids / Q000187:drug effects / Q000378:metabolism*
chemical_list: D001562:Benzimidazoles; D009942:Organometallic Compounds; D045322:Photosynthetic Reaction Center Complex Proteins; C412909:tris(2-guanidinobenzimidazole)chromium(III); C412908:tris(2-guanidinobenzimidazole)cobalt(III); D000255:Adenosine Triphosphate