Chodavarapu, S., Gomez, R., Vicente, M., and Kaguni, J.M. We also used strains genetically inactivated in each pathway to assess their relative effectiveness in regulating initiation when the level of DnaA protein was elevated. The second is that, because the unwound structure is thought to be sufficient for DnaB to bind, the mutant DnaA should be active in DNA replication from oriC. 2013
Citation:
Drs. 2009. The epitope recognized by the antibody has been determined. Termination requires tus gene product, which recognizes and binds to the ter sequence and stop the progress of replication fork. This project investigates the molecular mechanisms of initiation of DNA replication and its regulation. Flow cytometry experiments comparing isogenic dps+ and dps::kan strains suggest that Dps reduces the frequency of initiations. We also expected to identify genes such as seqA whose products act directly at oriC to inhibit extra initiations, and other classes of genes that either slow the rate of replication fork movement to reduce the frequency of collision with newly propagated forks, with a downstream stalled fork, or that minimize or prevent forks from Simmons, L. A., Felczak, M. and Kaguni, J. M. 2003. DnaB bound to the separated parental DNA strands then translocates on the DNA to further unwind the parental duplex. Awaiting Publication
2013
Because HU is relatively stable, the composition of HU in stationary phase cells is the heterodimer and the Primase then synthesizes primers that are extended by DNA polymerase III holoenzyme to duplicate the chromosome. Finally, biochemical characterization of DnaA protein indicates that it binds in an ordered manner to the chromosomal origin.Impacts(N/A)Publications, Progress 01/01/93 to 12/30/93OutputsThe long range objectives of this research are to understand biochemically the initiation of chromosomal replication, and its regulation. J. Biol. Book Chapters
The hypothesis underlying this aim is that these proteins affect the activity of DnaA to modulate the frequency of initiation in response to different in vivo conditions. Year Published:
We found that ATP or ADP but not AMP or cAMP stabilized monomeric DnaA. What opportunities for training and professional development has the project provided? Other experiments have focussed on the identification of amino acids of DnaA protein that interact with DnaB. have been published in Nucleic Acids Research, an "open access" journal. Awaiting Publication
As DnaA oligomerization is essential for initiation, DnaA seems like other AAA+ proteins which assemble into oligomeric structures. Ludlam, A.V., Basa, J.D. homodimer of two beta subunits. This work has been published in a peer-reviewed journal. We discovered that Dps specifically interacts with the N-terminal region of DnaA protein by affinity chromatography and a solid phase binding assay. We suggest that the presence of this gene in E. coli provides a growth advantage. Comparable experiments were performed to determine the stoichiometry of replication proteins in the prepriming complex that assembles at the E. coli chromosomal origin. PARTICIPANTS: Dr. Magdalena M. Felczak is a postdoctoral fellow who conducted the experiments in the relevant publication. opening of oriC is insufficient to provide a structure to which DnaB can stably interact.ImpactsChromosomal DNA replication is an essential process that is controlled at the level of initiation of DNA replication. These will also be studied biochemically.ImpactsChromosomal DNA replication is an essential process that is controlled at the level of initiation of DNA replication. 1997. Biology Test 5 - Plant Physiology (Photosynthesis, Respiration, Growth Hormones), Genetics (Genetic Material And Genetic Engineering), Mammals, Database Replication - Database Management. 276:44919-44925. (2013) In DNA Replication, S.P. ImpactsWhat was accomplished under these goals? Because DnaA protein appears to regulate the initiation process, we studied a mutant form, DnaAcos, which induces hyperactive initiation and is apparently defective in regulation. Listing of municipally and community sponsored retail farmers' markets in Michigan. 1997. (2013) The Encyclopedia of Biological Chemistry, 2e. Submitted. Chem. One monoclonal antibody that interferes with the interaction between DnaA protein and DnaB helicase implicates a region of DnaA protein involved in this interaction. Elsevier Science. A genetic method to analyze essential genes of Escherichia coli. Progress in the last granting period includes purification of a factor and its identification as grpE protein. is done on EduRev Study Group by NEET Students. These observations support a model whereby DnaA interacts with the alpha dimer or the alpha-beta heterodimer, depending on their cellular abundance, to recruit the respective forms of HU to oriC. In a manuscript under review, this gene encoded by the cryptic rac prophage has been named rcbA for its ability to reduce the frequency of chromosome breaks. Manuscripts that are in preparation describe the interaction of DnaC with DnaB, and that this interaction traps DnaB in a conformation whereby adjacent DnaB protomers of the DnaB toroid are separated to form a gap in the DnaB ring. DNA synthesis prompted an examination of the temporal expression of dnaK in E. coli. is altered so that it cannot be reused. HWANG, D.S., and KAGUNI, J.M. Drs. The finding of only a single DnaB hexamer bound per ssDNA suggests that a mechanism regulates the number of DnaB hexamers that can bind. The work leading to this publication is part of their training and professional development. Escherichia coli DnaA protein binds to the chromosomal origin to initiate chromosomal DNA replication. The second (Y271H) stabilizes the activity of the mutant protein carrying the A184V substitution. Two approaches taken to address this problem are i) to characterize mutant forms of DnaA protein, and ii) to correlate structural domains of DnaA protein to its various functions. Biochimie 88: 1-10. 262, 10475-10480). Status:
The dnaAcos allele of Escherichia coli: hyperactive initiation is caused by substitution of A184V and Y271H, resulting in defective ATP binding and aberrant DNA replication control. Felczak, M.M., Simmons, L.A., and Kaguni, J.M. p. 65. MARSZALEK, J., and KAGUNI, J.M. Primers formed by primase are then extended by DNA polymerase III holoenzyme. In contrast, induced expression of dnaA+ from a multicopy plasmid increases initiation frequency but viability is maintained. Primase Directs the Release of DnaC from DnaB. Other missense alleles may be defective in binding to DnaB. DnaC forms a complex with DnaB helicase, and this complex is required for this helicase to bind to the E. coli chromosomal origin. This information may be important to medicine and agriculture. Elsevier Science pp. Earlier, we showed by quantitative methods that an elevated level of DnaA induces extra initiations. The E. coli DnaB-DnaC complex and not DnaB alone is the active assembly that functions in the entry of DnaB helicase at the bacterial chromosomal origin. Published
), ISBN: 978-953-307-629-4 InTech, Available from: http://www.intechopen.com/articles/show/title/understanding-protein-f unction-the-disparity-between-bioinformatics-nd-molecular-methods, Kaguni, J.M. In E. coli, chromosomal replication is strictly regulated to occur at a specific time in the bacterial cell cycle. We showed by affinity chromatography and a solid phase Question bank for NEET. Characterization of R281A revealed that its inactivity in initiation is from its inability to properly assemble the prepriming complex. Staff Report 93:49. 2009. Performance & security by Cloudflare, Please complete the security check to access. An essential tryptophan of Escherichia coli DnaA protein functions in oligomerization at the E. coli replication origin. In the past 2 years, we have studied genetically and biochemically mutants we obtained by a novel genetic method. Elsevier Science pp. Of particular interest, the properties of one mutant suggest that it fails to respond to a novel regulatory factor. In other work, we studied specific dnaA alleles that reduce initiation frequency and chromosome content per cell at 34 to 39oC and fail to support initiation at both 20 and 44oC. in press. 266. Staff Report 93-52. pp. We have established a model in vitro system composed of highly purified proteins and a supercoiled plasmid template carrying a chromosomal origin that has revealed the individual events at the stage of initiation. Published
Current experiments show that an elevated level of this ribosomal protein also interferes with the initiation of bacterial DNA replication in vivo.