The interaction between the archaeal elongation factor 1α and its nucleotide exchange factor 1β

AbstractIn Sulfolobus solfataricus the binding of the exchange factor 1β (SsEF-1β) to SsEF-1α·GDP displaces the nucleotide and the SsEF-1α·SsEF-1β complex is formed. The complex itself is stable, but it dissociates upon the addition of GDP or Gpp(NH)p but not ATP. Since the rate of the formation of the SsEF-1α·SsEF-1β complex is significatively slower than the rate of the nucleotide exchange catalyzed by SsEF-1β it can be inferred that in vivo the GDP/GTP exchange reaction proceeds via an SsEF-1α–SsEF-1β interaction without involving the formation of a stable binary complex as an intermediate