PMID:7592800

Citation	Arvidson, CG and So, M (1995) The Neisseria transcriptional regulator PilA has a GTPase activity. J. Biol. Chem. 270:26045-8
Abstract	The pilA gene of Neisseria gonorrhoeae encodes the response regulator of a two-component regulatory system that controls pilin gene expression. Examination of the primary sequence of PilA indicates that the protein contains at least two functional domains. The N-terminal region has a proposed helix-turn-helix motif thought to be involved in DNA binding. This region also contains the residues that are presumed to form the acidic pocket involved in phosphorylation by PilB, the sensor kinase of the system. The C terminus of the protein has extensive homology to the G (GTP-binding) domains of the eukaryotic signal recognition particle (SRP) 54-kDa protein and the alpha subunit of the SRP receptor, or docking protein. This homology also extends to similar regions of the bacterial SRP homologs Ffh and FtsY. Here, we demonstrate that purified PilA has significant GTPase activity, and that this activity has an absolute requirement for MgCl2 and is sensitive to KCl and low pH. We also show that PilA has a strict specificity for GTP, and that GTP hydrolysis follows first order kinetics, with a maximum velocity (Vmax) of 1900 pmol of Pi produced per min per mg of protein and a Km for GTP of 9.6 microM at 37 degrees C.
Links	PubMed
Keywords	Bacterial Outer Membrane Proteins/biosynthesis; Bacterial Proteins/genetics; Bacterial Proteins/isolation & purification; Bacterial Proteins/metabolism; DNA-Binding Proteins/genetics; DNA-Binding Proteins/isolation & purification; DNA-Binding Proteins/metabolism; Escherichia coli/genetics; Fimbriae Proteins; GTP Phosphohydrolases/genetics; GTP Phosphohydrolases/isolation & purification; GTP Phosphohydrolases/metabolism; Gene Expression Regulation, Bacterial; Genes, Bacterial; Kinetics; Mathematics; Neisseria gonorrhoeae/enzymology; Neisseria gonorrhoeae/genetics; Pili, Sex; Ribonucleotides/pharmacology
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
NEIGO:Q5G2R0		GO:0003924: GTPase activity	ECO:0000314:		F		figure 2	complete
NEIGO:Q5G2Q5	Contributes to	GO:0003924: GTPase activity	ECO:0000314:		F		Table 2 shows that PilA specifically hydrolyzes GTP	complete CACAO 4666

References

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