Structure and Activity of PA5508, a Hexameric Glutamine Synthetase Homologue.
Ladner, J.E., Atanasova, V., Dolezelova, Z., Parsons, J.F.(2012) Biochemistry 51: 10121-10123
- PubMed: 23234431 
- DOI: https://doi.org/10.1021/bi3014856
- Primary Citation of Related Structures:  
4HPP - PubMed Abstract: 
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.
Organizational Affiliation: 
Institute for Bioscience and Biotechnology Research, University of Maryland, MD, USA.