Organization and gene expression within restriction-modification systems of Herpetosiphon giganteus.


Journal Article

We have characterized a family of related restriction-modification (R-M) systems from the soil bacterium Herpetosiphon giganteus (Hgi). A comparison of their genetic organization reveals two types of regulatory proteins, called controlling ORF C. While one of these small reading frames derived from RM.HgiCI seems to be an enhancer of its own promoter, evidence is provided for a silencer function of the other ORF C derived from the closely related AvaII-type systems RM.HgiBI/CII/EI. The respective silencer function is detected during our various attempts to clone three isoschizomers with unusually high differences in their specific activity. Sequencing and site-directed mutagenesis revealed just two amino acids as being responsible for a massive increase in specific activity of these endonucleases.

Full Text

Cited Authors

  • Kröger, M; Blum, E; Deppe, E; Düsterhöft, A; Erdmann, D; Kilz, S; Meyer-Rogge, S; Möstl, D

Published Date

  • May 1995

Published In

Volume / Issue

  • 157 / 1-2

Start / End Page

  • 43 - 47

PubMed ID

  • 7607523

Pubmed Central ID

  • 7607523

Electronic International Standard Serial Number (EISSN)

  • 1879-0038

International Standard Serial Number (ISSN)

  • 0378-1119

Digital Object Identifier (DOI)

  • 10.1016/0378-1119(94)00779-r


  • eng