A motif conserved among the type I restriction-modification enzymes and antirestriction proteins: a possible basis for mechanism of action of plasmid-encoded antirestriction functions.
AUTOR(ES)
Belogurov, A A
RESUMO
Antirestriction proteins Ard encoded by some self-transmissible plasmids specifically inhibit restriction by members of all three families of type I restriction-modification (R-M) systems in E.coli. Recently, we have identified the amino acid region, 'antirestriction' domain, that is conserved within different plasmid and phage T7-encoded antirestriction proteins and may be involved in interaction with the type I R-M systems. In this paper we demonstrate that this amino acid sequence shares considerable similarity with a well-known conserved sequence (the Argos repeat) found in the DNA sequence specificity (S) polypeptides of type I systems. We suggest that the presence of these similar motifs in restriction and antirestriction proteins may give a structural basis for their interaction and that the antirestriction action of Ard proteins may be a result of the competition between the 'antirestriction' domains of Ard proteins and the similar conserved domains of the S subunits that are believed to play a role in the subunit assembly of type I R-M systems.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=306760Documentos Relacionados
- Cloning and Characterization of the Lactococcal Plasmid-Encoded Type II Restriction/Modification System, LlaDII
- Structural homologies among type I restriction-modification systems.
- Role and Mechanism of Action of C · PvuII, a Regulatory Protein Conserved among Restriction-Modification Systems
- Cloning and sequence analysis of the StsI restriction-modification gene: presence of homology to FokI restriction-modification enzymes.
- Characterization of the archaeal, plasmid-encoded type II restriction-modification system MthTI from Methanobacterium thermoformicicum THF: homology to the bacterial NgoPII system from Neisseria gonorrhoeae.