This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Thirlway, J. Articles by Soultanas, P. Search for Related Content PubMed PubMed Citation Articles by Thirlway, J. Articles by Soultanas, P.

 Previous Article  |  Next Article 

Journal of Bacteriology, February 2006, p. 1534-1539, Vol. 188, No. 4
0021-9193/06/$08.00+0     doi:10.1128/JB.188.4.1534-1539.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

In the Bacillus stearothermophilus DnaB-DnaG Complex, the Activities of the Two Proteins Are Modulated by Distinct but Overlapping Networks of Residues

Jenny Thirlway and Panos Soultanas^*

Centre for Biomolecular Sciences (CBS), School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom

Received 14 October 2005/ Accepted 30 November 2005

We demonstrate the primase activity of Bacillus stearothermophilus DnaG and show that it initiates at 3'-ATC-5' and 3'-ATT-5' sites synthesizing primers that are 22 or 23 nucleotides long. In the presence of the helicase DnaB the size distribution of primers is different, and a range of additional smaller primers are also synthesized. Nine residues from the N- and C-terminal domains of DnaB, as well as its linker region, have been reported previously to affect this interaction. In Bacillus stearothermophilus only three residues from the linker region (I119 and I125) and the N-terminal domain (Y88) of DnaB have been shown previously to have direct structural importance, and I119 and I125 mediate DnaG-induced effects on DnaB activity. The functions of the other residues (L138, T191, E192, R195, and M196) are still a mystery. Here we show that the E15A, Y88A, and E15A Y88A mutants bind DnaG but are not able to modulate primer size, whereas the R195A M196A mutant inhibited the primase activity. Therefore, four of these residues, E15 and Y88 (N-terminal domain) and R195 and M196 (C-terminal domain), mediate DnaB-induced effects on DnaG activity. Overall, the data suggest that the effects of DnaB on DnaG activity and vice versa are mediated by distinct but overlapping networks of residues.

---

* Corresponding author. Mailing address: Centre for Biomolecular Sciences (CBS), School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom. Phone: 44-(0)-115-9513525. Fax: 44-(0)-115-8468002. E-mail: panos.soultanas{at}nottingham.ac.uk.

---

Journal of Bacteriology, February 2006, p. 1534-1539, Vol. 188, No. 4
0021-9193/06/$08.00+0     doi:10.1128/JB.188.4.1534-1539.2006
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Larson, M. A., Bressani, R., Sayood, K., Corn, J. E., Berger, J. M., Griep, M. A., Hinrichs, S. H. (2008). Hyperthermophilic Aquifex aeolicus initiates primer synthesis on a limited set of trinucleotides comprised of cytosines and guanines. Nucleic Acids Res 36: 5260-5269 [Abstract] [Full Text]  
• Bailey, S., Eliason, W. K., Steitz, T. A. (2007). Structure of Hexameric DnaB Helicase and Its Complex with a Domain of DnaG Primase. Science 318: 459-463 [Abstract] [Full Text]  
• Bailey, S., Eliason, W. K., Steitz, T. A. (2007). The crystal structure of the Thermus aquaticus DnaB helicase monomer. Nucleic Acids Res 35: 4728-4736 [Abstract] [Full Text]  
• Koepsell, S. A., Larson, M. A., Griep, M. A., Hinrichs, S. H. (2006). Staphylococcus aureus Helicase but Not Escherichia coli Helicase Stimulates S. aureus Primase Activity and Maintains Initiation Specificity. J. Bacteriol. 188: 4673-4680 [Abstract] [Full Text]