This Article Full Text Full Text (PDF) Supplemental material 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 Google Scholar Google Scholar Articles by Lin, Y. Articles by Cann, I. K. O. Search for Related Content PubMed PubMed Citation Articles by Lin, Y. Articles by Cann, I. K. O.

Methanosarcina acetivorans Flap Endonuclease 1 Activity Is Inhibited by a Cognate Single-Stranded-DNA-Binding Protein

Department of Animal Sciences,¹ Department of Physics,² Department of Biochemistry,³ Institute for Genomic Biology,⁴ Howard Hughes Medical Institute,⁵ Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801⁶

Received 11 January 2006/ Accepted 11 June 2006

The oligonucleotide/oligosaccharide-binding (OB) fold is central to the architecture of single-stranded- DNA-binding proteins, which are polypeptides essential for diverse cellular processes, including DNA replication, repair, and recombination. In archaea, single-stranded DNA-binding proteins composed of multiple OB folds and a zinc finger domain, in a single polypeptide, have been described. The OB folds of these proteins were more similar to their eukaryotic counterparts than to their bacterial ones. Thus, the archaeal protein is called replication protein A (RPA), as in eukaryotes. Unlike most organisms, Methanosarcina acetivorans harbors multiple functional RPA proteins, and it was our interest to determine whether the different proteins play different roles in DNA transactions. Of particular interest was lagging-strand DNA synthesis, where recently RPA has been shown to regulate the size of the 5' region cleaved during Okazaki fragment processing. We report here that M. acetivorans RPA1 (MacRPA1), a protein composed of four OB folds in a single polypeptide, inhibits cleavage of a long flap (20 nucleotides) by M. acetivorans flap endonuclease 1 (MacFEN1). To gain a further insight into the requirement of the different regions of MacRPA1 on its inhibition of MacFEN1 endonuclease activity, N-terminal and C-terminal truncated derivatives of the protein were made and were biochemically and biophysically analyzed. Our results suggested that MacRPA1 derivatives with at least three OB folds maintained the properties required for inhibition of MacFEN1 endonuclease activity. Despite these interesting observations, further biochemical and genetic analyses are required to gain a deeper understanding of the physiological implications of our findings.

Supplemental material for this article may be found at http://jb.asm.org/.