PMID:23352854

Citation	Williams, KJ, Bennett, MH, Barton, GR, Jenkins, VA and Robertson, BD (2013) Adenylylation of mycobacterial Glnk (PII) protein is induced by nitrogen limitation. Tuberculosis (Edinb) 93:198-206
Abstract	PII proteins are pivotal regulators of nitrogen metabolism in most prokaryotes, controlling the activities of many targets, including nitrogen assimilation enzymes, two component regulatory systems and ammonium transport proteins. Escherichia coli contains two PII-like proteins, PII (product of glnB) and GlnK, both of which are uridylylated under nitrogen limitation at a conserved Tyrosine-51 residue by GlnD (a uridylyl transferase). PII-uridylylation in E. coli controls glutamine synthetase (GS) adenylylation by GlnE and mediates the NtrB/C transcriptomic response. Mycobacteria contain only one PII protein (GlnK) which in environmental Actinomycetales is adenylylated by GlnD under nitrogen limitation. However in mycobacteria, neither the type of GlnK (PII) covalent modification nor its precise role under nitrogen limitation is known. In this study, we used LC-Tandem MS to analyse the modification state of mycobacterial GlnK (PII), and demonstrate that during nitrogen limitation GlnK from both non-pathogenic Mycobacterium smegmatis and pathogenic Mycobacterium tuberculosis is adenylylated at the Tyrosine-51 residue; we also show that GlnD is the adenylyl transferase enzyme responsible. Further analysis shows that in contrast to E. coli, GlnK (PII) adenylylation in M. tuberculosis does not regulate GS adenylylation, nor does it mediate the transcriptomic response to nitrogen limitation.
Links	PubMed PMC3612183 Online version:10.1016/j.tube.2012.12.003
Keywords	Bacterial Proteins/metabolism; Bacterial Proteins/physiology; Cell-Free System/metabolism; Gene Expression Regulation, Bacterial/physiology; Genes, Bacterial; Glutamate-Ammonia Ligase/metabolism; Mycobacterium smegmatis/genetics; Mycobacterium smegmatis/metabolism; Mycobacterium tuberculosis/genetics; Mycobacterium tuberculosis/metabolism; Nitrogen/deficiency; Nitrogen/metabolism; PII Nitrogen Regulatory Proteins/metabolism; PII Nitrogen Regulatory Proteins/physiology; Protein Processing, Post-Translational; Stress, Physiological/genetics; Stress, Physiological/physiology; Tandem Mass Spectrometry/methods
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
MYCTU:GLND		GO:0070566: adenylyltransferase activity	ECO:0000315:		F		glnD deletion mutant was unable to adenylylate GlnK, while it was adenylylated in the wild type strain (Suppl. Figure S2).	complete CACAO 9075
MYCTU:GLND	enables	GO:0070566: adenylyltransferase activity	ECO:0000315: mutant phenotype evidence used in manual assertion		F		Seeded From UniProt	complete

References

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