Open AccessStructure of the dimeric form of CTP synthase from Sulfolobus solfataricus
Author(s) -
Lauritsen Iben,
Willemoës Martin,
Jensen Kaj Frank,
Johansson Eva,
Harris Pernille
Publication year - 2011
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309110052334
Subject(s) - sulfolobus solfataricus , thermus thermophilus , tetramer , atp synthase , dimer , enzyme , chemistry , nucleotide , biochemistry , stereochemistry , active site , crystallography , escherichia coli , archaea , gene , organic chemistry
CTP synthase catalyzes the last committed step in de novo pyrimidine‐nucleotide biosynthesis. Active CTP synthase is a tetrameric enzyme composed of a dimer of dimers. The tetramer is favoured in the presence of the substrate nucleotides ATP and UTP; when saturated with nucleotide, the tetramer completely dominates the oligomeric state of the enzyme. Furthermore, phosphorylation has been shown to regulate the oligomeric states of the enzymes from yeast and human. The crystal structure of a dimeric form of CTP synthase from Sulfolobus solfataricus has been determined at 2.5 Å resolution. A comparison of the dimeric interface with the intermolecular interfaces in the tetrameric structures of Thermus thermophilus CTP synthase and Escherichia coli CTP synthase shows that the dimeric interfaces are almost identical in the three systems. Residues that are involved in the tetramerization of S. solfataricus CTP synthase according to a structural alignment with the E. coli enzyme all have large thermal parameters in the dimeric form. Furthermore, they are seen to undergo substantial movement upon tetramerization.