Proteolysis of the type III glutamine synthetase from Bacteroides fragilis causes expedient crystal-packing rearrangements

作者：van Rooyen Jason^*; Belrhali Hassan; Abratt Valarie; Sewell B Trevor

来源：Acta Crystallographica Section F-Structural Biology and Crystallization Communications, 2011, 67: 358-363.

DOI：10.1107/S1744309110053893

• glutamine synthetase III
• Bacteroides fragilis

This work details the intentional modifications that led to the first structure of a type III glutamine synthetase enzyme (GSIII). This approach followed the serendipitous discovery of digestion caused by an extracellular protease from a contaminating bacterium, Pseudomonas fluorescens. The protease only cleaves the GSIII protein at a single site, leaving the oligomer intact but allowing the protein to crystallize in a different space group. This transition from space group P1 to space group C222(1) is accompanied by improved growth characteristics, more reproducible diffraction and enhanced mechanical stability. The crystallographic analyses presented here provide the structural basis of the altered molecular packing in the full-length and digested crystal forms and suggest modifications for future structural studies.

• 出版日期2011-3