SINGLE-STRANDED-DNA BINDING-PROTEIN ENCODED BY THE FILAMENTOUS BACTERIOPHAGE-M13 - STRUCTURAL AND FUNCTIONAL-CHARACTERISTICS

The single-stranded DNA binding protein, or gene V protein (gVp), enco ded by gene V of the filamentous bacteriophage M13 is a multifunctiona l protein that not only regulates viral DNA replication but also gene expression at the level of mRNA translation. It furthermore is implica ted as a scaffolding and/or chaperone protein during the phage assembl y process at the hostcell membrane. The protein is 87 amino acids long and its biological functional entity is a homodimer. In this manuscri pt a short description of the life cycle of filamentous phages is pres ented and our current knowledge of the major functional and structural properties and characteristics of gene V protein are reviewed. In add ition models of the superhelical complexes gVp forms with ssDNA are de scribed and their (possible) biological meaning in the infection proce ss are discussed. Finally it is described that the 'DNA binding loop' of gVp is a recurring motif in many ssDNA binding proteins and that th e fold of gVp is shared by a large family of evolutionarily conserved gene regulatory proteins.