Dynamics and activation in response regulators: the β4-α4 loop.

Thumbnail Image



Journal Title

Journal ISSN

Volume Title

Repository Usage Stats


Citation Stats


Two-component signal transduction systems of microbes are a primary means to respond to signals emanating from environmental and metabolic fluctuations as well as to signals coordinating the cell cycle with macromolecular syntheses, among a large variety of other essential roles. Signals are recognized by a sensor domain of a histidine kinase which serves to convert signal binding to an active transmissible phosphoryl group through a signal-induced ATP-dependent autophosphorylation reaction directed to histidine residue. The sensor kinase is specifically mated to a response regulator, to which it transfers the phosphoryl group that activates the response regulator's function, most commonly gene repression or activation but also interaction with other regulatory proteins. Two-component systems have been genetically amplified to control a wide variety of cellular processes; for example, both Escherichia coli and Pseudomonas aeruginosa have 60 plus confirmed and putative two-component systems. Bacillus subtilis has 30 plus and Nostoc punctiformis over 100. As genetic amplification does not result in changes in the basic structural folds of the catalytic domains of the sensor kinase or response regulators, each sensor kinase must recognize its partner through subtle changes in residues at the interaction surface between the two proteins. Additionally, the response regulator must prepare itself for efficient activation by the phosphorylation event. In this short review, we discuss the contributions of the critical β4-α4 recognition loop in response regulators to their function. In particular, we focus on this region's microsecond-millisecond timescale dynamics propensities and discuss how these motions play a major role in response regulator recognition and activation.





Published Version (Please cite this version)


Publication Info

Bobay, Benjamin G, James A Hoch and John Cavanagh (2012). Dynamics and activation in response regulators: the β4-α4 loop. Biomolecular concepts, 3(2). pp. 175–182. 10.1515/bmc-2011-0063 Retrieved from https://hdl.handle.net/10161/28896.

This is constructed from limited available data and may be imprecise. To cite this article, please review & use the official citation provided by the journal.



Benjamin Bobay

Assistant Professor in Radiology

I am the Assistant Director of the Duke University NMR Center and an Assistant Professor in the Duke Radiology Department. I was originally trained as a structural biochemist with an emphasis on utilizing NMR and continue to use this technique daily helping collaborators characterize protein structures and small molecules through a diverse set of NMR experiments. Through the structural characterization of various proteins, from both planta and eukaryotes, I have developed a robust protocol of utilizing computational biology for describing binding events, mutations, post-translations modifications (PTMs), and/or general behavior within in silico solution scenarios. I have utilized these techniques in collaborations ranging from plant pathologists at the Swammerdam Institute for Life Sciences department at the University of Amsterdam to biomedical engineers at North Carolina State University to professors in the Pediatrics department at Duke University. These studies have centered around the structural and functional consequences of PTMs (such as phosphorylation), mutation events, truncation of multi-domain proteins, dimer pulling experiments, to screening of large databases of ligands for potential binding events. Through this combination of NMR and computational biology I have amassed 50 peer-reviewed published articles and countless roles on scientific projects, as well as the development of several tutorials concerning the creation of ligand databases and high-throughput screening of large databases utilizing several different molecular dynamic and computational docking programs.

Unless otherwise indicated, scholarly articles published by Duke faculty members are made available here with a CC-BY-NC (Creative Commons Attribution Non-Commercial) license, as enabled by the Duke Open Access Policy. If you wish to use the materials in ways not already permitted under CC-BY-NC, please consult the copyright owner. Other materials are made available here through the author’s grant of a non-exclusive license to make their work openly accessible.