The bridge helix coordinates movements of modules in RNA polymerase
1 Department of Biochemistry, University of Wisconsin-Madison, 5441 Microbial Sciences, 1550 Linden Drive, Madison, WI 53706, USA
2 Department of Bacteriology, University of Wisconsin-Madison, 5441 Microbial Sciences, 1550 Linden Drive, Madison, WI 53706, USA
BMC Biology 2010, 8:141 doi:10.1186/1741-7007-8-141Published: 29 November 2010
The RNA polymerase 'bridge helix' is a metastable α-helix that spans the leading edge of the enzyme active-site cleft. A new study published in BMC Biology reveals surprising tolerance to helix-disrupting changes in a region previously thought crucial for translocation, and suggests roles for two hinge-like segments of the bridge helix in coordinating modules that move during the nucleotide-addition cycle.