The N-terminal part of theE.ColiDNA binding protein FIS is essential for stimulating site-specific DNA inversion but is not required for specific DNA binding

Abstract

FIS protein is involved in several different cellular processes stimulating site-specific recombination in phages Mu and λ as well as transcription of stable RNA operons in E.coli . We have performed a mutational analysis of fis and provide genetic and biochemical evidence that a truncated version of FIS lacking the Nterminal region is sufficient for specific DNA binding and for stimulating λ excision. These mutants also retain their ability to autoregulate fis gene expression. Such mutant proteins, however, cannot stimulate the enhancer dependent DNA inversion reaction.