GONUTS has been updated to MW1.31 Most things seem to be working but be sure to report problems.

Have any questions? Please email us at ecoliwiki@gmail.com


Jump to: navigation, search

Strycharska, MS, Arias-Palomo, E, Lyubimov, AY, Erzberger, JP, O'Shea, VL, Bustamante, CJ and Berger, JM (2013) Nucleotide and partner-protein control of bacterial replicative helicase structure and function. Mol. Cell 52:844-54


Cellular replication forks are powered by ring-shaped, hexameric helicases that encircle and unwind DNA. To better understand the molecular mechanisms and control of these enzymes, we used multiple methods to investigate the bacterial replicative helicase, DnaB. A 3.3 Å crystal structure of Aquifex aeolicus DnaB, complexed with nucleotide, reveals a newly discovered conformational state for this motor protein. Electron microscopy and small angle X-ray scattering studies confirm the state seen crystallographically, showing that the DnaB ATPase domains and an associated N-terminal collar transition between two physical states in a nucleotide-dependent manner. Mutant helicases locked in either collar state are active but display different capacities to support critical activities such as duplex translocation and primase-dependent RNA synthesis. Our findings establish the DnaB collar as an autoregulatory hub that controls the ability of the helicase to transition between different functional states in response to both nucleotide and replication initiation/elongation factors.


PubMed PMC3929961 Online version:10.1016/j.molcel.2013.11.016


Adenosine Triphosphate/metabolism; Amino Acid Sequence; Bacterial Proteins/chemistry; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Binding Sites; Crystallography, X-Ray; DNA Replication; DNA, Bacterial/biosynthesis; DnaB Helicases/chemistry; DnaB Helicases/genetics; DnaB Helicases/metabolism; Escherichia coli Proteins/chemistry; Escherichia coli Proteins/genetics; Escherichia coli Proteins/metabolism; Hydrolysis; Microscopy, Electron; Models, Molecular; Molecular Sequence Data; Mutation; Nucleotides/metabolism; Protein Conformation; RNA, Bacterial/biosynthesis; Recombinant Proteins/metabolism; Structure-Activity Relationship



Gene product Qualifier GO Term Evidence Code with/from Aspect Extension Notes Status


GO:0032508: DNA duplex unwinding



"When the dilated and constricted mutants were tested in a single-turnover, fork-unwinding assay with DnaC, the dilated mutant was able to produce ∼20% more unwound product as the wild-type helicase and did so at a slightly faster rate (Figure 5B). By contrast, while the constricted mutant could generate an amount of ssDNA comparable to that of wild-type DnaB, it took longer to do so (Figure 5B)."

CACAO 11910


See also


See Help:References for how to manage references in GONUTS.