Crystal Structures of Two Isozymes of Citrate Synthase from Sulfolobus tokodaii Strain 7.

ABSTRACT: Thermoacidophilic archaeon Sulfolobus tokodaii strain 7 has two citrate synthase genes (ST1805-CS and ST0587-CS) in the genome with 45% sequence identity. Because they exhibit similar optimal temperatures of catalytic activity and thermal inactivation profiles, we performed structural comparisons between these isozymes to elucidate adaptation mechanisms to high temperatures in thermophilic CSs. The crystal structures of ST1805-CS and ST0587-CS were determined at 2.0 Å and 2.7 Å resolutions, respectively. Structural comparison reveals that both of them are dimeric enzymes composed of two identical subunits, and these dimeric structures are quite similar to those of citrate synthases from archaea and eubacteria. ST0587-CS has, however, 55 ion pairs within whole dimer structure, while having

SUBMITTER: Murakami M 

PROVIDER: S-EPMC5021468 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature