Ligand binding and structural changes associated with allostery in yeast NAD +-specific isocitrate dehydrogenase

Lee McAlister-Henn

Resultado de la investigación: Review articlerevisión exhaustiva

9 Citas (Scopus)


Yeast NAD +-specific isocitrate dehydrogenase (IDH) is an octameric enzyme composed of four each of regulatory IDH1 and catalytic IDH2 subunits that share 42% sequence identity. IDH2 contains catalytic isocitrate/Mg 2+ and NAD + binding sites whereas IDH1 contains homologous binding sites, respectively, for cooperative binding of isocitrate and for allosteric binding of AMP. Ligand binding is highly ordered in vitro, and IDH exhibits the unusual property of half-site binding for all ligands. The structures of IDH solved in the absence or presence of ligands have shown: (a) a heterodimer to be the basic structural/functional unit of the enzyme, (b) the organization of heterodimers to form tetramer and octamer structures, (c) structural differences that may underlie cooperative and allosteric regulatory mechanisms, and (d) the possibility for formation of a disulfide bond that could reduce catalytic activity. In vivo analyses of mutant enzymes have elucidated the physiological importance of catalytic activity and allosteric regulation of this tricarboxylic acid cycle enzyme. Other studies have established the importance of a disulfide bond in regulation of IDH activity in vivo, as well as contributions of this bond to the property of half-site ligand binding exhibited by the wild-type enzyme.

Idioma originalEnglish (US)
Páginas (desde-hasta)112-117
Número de páginas6
PublicaciónArchives of Biochemistry and Biophysics
EstadoPublished - mar 15 2012
Publicado de forma externa

ASJC Scopus subject areas

  • Molecular Biology
  • Biophysics
  • Biochemistry


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