TY - JOUR
T1 - The Neisseria transcriptional regulator PilA has a GTPase activity
AU - Arvidson, C. G.
AU - So, M.
PY - 1995/11/3
Y1 - 1995/11/3
N2 - 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 α 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 (V(max)) of 1900 pmol of P(i) produced per min per mg of protein and a K(m) for GTP of 9.6 μM at 37 °C.
AB - 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 α 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 (V(max)) of 1900 pmol of P(i) produced per min per mg of protein and a K(m) for GTP of 9.6 μM at 37 °C.
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U2 - 10.1074/jbc.270.44.26045
DO - 10.1074/jbc.270.44.26045
M3 - Article
C2 - 7592800
AN - SCOPUS:0028798996
SN - 0021-9258
VL - 270
SP - 26045
EP - 26048
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 44
ER -