|Title||Structure and activity of PA5508, a hexameric glutamine synthetase homologue.|
|Publication Type||Journal Article|
|Year of Publication||2012|
|Authors||Ladner, JE, Atanasova, V, Dolezelova, Z, Parsons, JF|
|Date Published||2012 Dec 21|
|Keywords||Bacterial Proteins, Catalytic Domain, Crystallography, X-Ray, Glutamate-Ammonia Ligase, Models, Molecular, Polyamines, Protein Multimerization, Pseudomonas aeruginosa, Substrate Specificity|
The structure of PA5508 from Pseudomonas aeruginosa, a glutamine synthetase (GS) homologue, has been determined at 2.5 Å. Surprisingly, PA5508 forms single hexameric rings rather than the stacked double rings that are characteristic of GS. The C-terminal helical thong motif that links GS rings is present in PA5508; however, it is folded back toward the core of its own polypeptide, preventing it from interacting with a second ring. Interestingly, PA5508 displays a clear preference for aromatic amine substrates. Unique aspects of the structure illustrate how the enzyme is able to catalyze reactions involving bulky amines rather than ammonia.