Chimeras between single-stranded DNA-binding proteins from Escherichia coli and Mycobacterium tuberculosis reveal that their C-terminal domains interact with uracil DNA glycosylases

Priya, Handa and Narottam, Acharya and Umesh, Varshney (2001) Chimeras between single-stranded DNA-binding proteins from Escherichia coli and Mycobacterium tuberculosis reveal that their C-terminal domains interact with uracil DNA glycosylases. In: Journal of Biological Chemistry, 276 (20). pp. 16992-16997.

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Abstract

Uracil, a promutagenic base in DNA can arise by spontaneous deamination of cytosine or incorporation of dUMP by DNA polymerase. Uracil is removed from DNA by uracil DNA glycosylase (UDG), the first enzyme in the uracil excision repair pathway. We recently reported that the Escherichia coli single-stranded DNA binding protein (SSB) facilitated uracil excision from certain structured substrates by E. coli UDG (EcoUDG) and suggested the existence of interaction between SSB and UDG. In this study, we have made use of the chimeric proteins obtained by fusion of N- and C-terminal domains of SSBs from E. coli and Mycobacterium tuberculosis to investigate interactions between SSBs and UDGs. The EcoSSB or a chimera containing its C-terminal domain interacts with EcoUDG in a binary (SSB-UDG) or a ternary (DNA-SSB-UDG) complex. However, the chimera containing the N-terminal domain from EcoSSB showed no interactions with EcoUDG. Thus, the C-terminal domain (48 amino acids) of EcoSSB is necessary and sufficient for interaction with EcoUDG. The data also suggest that the C-terminal domain (34 amino acids) of MtuSSB is a predominant determinant for mediating its interaction with MtuUDG. The mechanism of how the interactions between SSB and UDG could be important in uracil excision repair pathway has been discussed.

Item Type:	Journal Article
Publication:	Journal of Biological Chemistry
Publisher:	American Society for Biochemistry and Molecular Biology
Additional Information:	copy right of this article belongs to American Society for Biochemistry and Molecular Biology
Keywords:	Biochemistry;Molecular Biophysics;Methods and Techniques
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	04 Oct 2007
Last Modified:	19 Sep 2010 04:40
URI:	http://eprints.iisc.ac.in/id/eprint/12055

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