Research Group "Chromosome Organization and Dynamics" (Stephan Gruber)
Chromosomes encode the wealth of genetic information in the sequence of bases in its DNA molecule. When laid out side by side the DNA molecules exceed the dimensions of the cell by several orders of magnitude – about three in bacteria and five in human cells. During cell division the two copies of the genetic material are highly condensed and tightly packed in the form of chromosomes to support their precise segregation to the emerging daughter cells. Faulty distribution of chromosomes during cell division can lead to severe birth defects or cancer. Stephan Gruber and his Research Group “Chromosome Organization and Dynamics” want to unravel how DNA is organized within chromosomes and how chromosomes are segregated into the daughter cells. The special interest of the group are Structural Maintenance of Chromosomes protein complexes, also called condensin. Condensin plays key roles in chromosome dynamics having related functions in bacteria and humans. The team has selected the bacterium Bacillus subtilis as a simple and powerful model organism to study the structure of the condensin complex and its role in mediating chromosome compaction. Condensin in bacteria is comprised of three proteins. Together they form a large ring-shaped structure that presumably entraps loops of DNA, thereby folding the chromosome into a more compact structure. The picture shows a hypothetical model of a central part of condensin at atomic resolution based on three separate X-ray crystal structures. Key proteins of chromosome segregation already play an important role as targets of antibiotics. A better understanding of these molecular mechanisms could facilitate the identification of new drug targets in bacterial pathogens.