Two modes of interaction of the single-stranded DNA-binding protein of bacteriophage T7 with the DNA polymerase-thioredoxin complex
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Permanent link to this recordhttp://hdl.handle.net/10754/561475
MetadataShow full item record
AbstractThe DNA polymerase encoded by bacteriophage T7 has low processivity. Escherichia coli thioredoxin binds to a segment of 76 residues in the thumb subdomain of the polymerase and increases the processivity. The binding of thioredoxin leads to the formation of two basic loops, loops A and B, located within the thioredoxin-binding domain (TBD). Both loops interact with the acidic C terminus of the T7 helicase. A relatively weak electrostatic mode involves the C-terminal tail of the helicase and the TBD, whereas a high affinity interaction that does not involve the C-terminal tail occurs when the polymerase is in a polymerization mode. T7 gene 2.5 single-stranded DNA-binding protein (gp2.5) also has an acidic C-terminal tail. gp2.5 also has two modes of interaction with the polymerase, but both involve the C-terminal tail of gp2.5. An electrostatic interaction requires the basic residues in loops A and B, and gp2.5 binds to both loops with similar affinity as measured by surface plasmon resonance. When the polymerase is in a polymerization mode, the C terminus of gene 2.5 protein interacts with the polymerase in regions outside the TBD.gp2.5 increases the processivity of the polymerase-helicase complex during leading strand synthesis. When loop B of the TBD is altered, abortive DNA products are observed during leading strand synthesis. Loop B appears to play an important role in communication with the helicase and gp2.5, whereas loop A plays a stabilizing role in these interactions. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.
JournalJournal of Biological Chemistry
PubMed Central IDPMC2878571
- Interactions of Escherichia coli thioredoxin, the processivity factor, with bacteriophage T7 DNA polymerase and helicase.
- Authors: Ghosh S, Hamdan SM, Cook TE, Richardson CC
- Issue date: 2008 Nov 14
- A unique loop in T7 DNA polymerase mediates the binding of helicase-primase, DNA binding protein, and processivity factor.
- Authors: Hamdan SM, Marintcheva B, Cook T, Lee SJ, Tabor S, Richardson CC
- Issue date: 2005 Apr 5
- The carboxyl-terminal domain of bacteriophage T7 single-stranded DNA-binding protein modulates DNA binding and interaction with T7 DNA polymerase.
- Authors: He ZG, Rezende LF, Willcox S, Griffith JD, Richardson CC
- Issue date: 2003 Aug 8
- Helicase-DNA polymerase interaction is critical to initiate leading-strand DNA synthesis.
- Authors: Zhang H, Lee SJ, Zhu B, Tran NQ, Tabor S, Richardson CC
- Issue date: 2011 Jun 7
- C-terminal phenylalanine of bacteriophage T7 single-stranded DNA-binding protein is essential for strand displacement synthesis by T7 DNA polymerase at a nick in DNA.
- Authors: Ghosh S, Marintcheva B, Takahashi M, Richardson CC
- Issue date: 2009 Oct 30