Research Summary

Structural studies on NTP-dependent Restriction-Modification Enzymes

Fundamental cellular processes rely on protein machines that use energy to perform specific tasks. Often, this involves orchestration of activities of various functional domains of the protein molecule. Our understanding of how these protein machines work is limited.

Nucleoside triphosphate (NTP) dependent restriction-modification (R-M) enzymes are protein machines that bind to a specific DNA sequence, perform sequence-specific methylation (modification), translocate DNA by hydrolysis of NTP and nucleolytically cleave it (restriction). Modification of host DNA protects it from restriction, while unmodified foreign DNA (eg bacteriophage DNA) is cleaved. The molecular basis of this fascinating interplay and regulation of activities of the R-M enzymes is not well understood

The principal aim of the project is to obtain a molecular framework for the function and regulation of NTP-dependent R-M enzymes through determination of their three-dimensional structures. The findings of the project will help unravel how R-M enzymes perform and coordinate their varied activities, and will also facilitate understanding of how other complex protein machines involved in nucleic acid transactions work.