Structure and activity of PA5508, a hexameric glutamine synthetase homologue.

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TitleStructure and activity of PA5508, a hexameric glutamine synthetase homologue.
Publication TypeJournal Article
Year of Publication2012
AuthorsLadner, JE, Atanasova, V, Dolezelova, Z, Parsons, JF
JournalBiochemistry
Volume51
Issue51
Pagination10121-3
Date Published2012 Dec 21
ISSN1520-4995
KeywordsBacterial Proteins, Catalytic Domain, Crystallography, X-Ray, Glutamate-Ammonia Ligase, Models, Molecular, Polyamines, Protein Multimerization, Pseudomonas aeruginosa, Substrate Specificity
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.

DOI10.1021/bi3014856
Alternate JournalBiochemistry
PubMed ID23234431