The Hauryliuk lab

University of Tartu

Institute of Technology

 
 

Our research centers around protein biosynthesis and its  regulation. There are three major directions.


First is the bacterial stringent response - an adaptation mechanism mediated by the alarmone nucleotide ppGpp, which exerts its regulatory role by attenuating the activity of numerous enzymes, with RNA polymerase being the main target. The intracellular levels of ppGpp are controlled by the RelA-SpoT Homologue (RSH) family of proteins, which either synthesize or hydrolyze ppGpp in response to various stress stimuli. We utilize a combination of experimental and in silico approaches. Using an in vitro stringent response system, we demonstrated that the E. coli RelA protein is activated by its product ppGpp, thus creating a regulatory positive feedback loop. By means of sensitive bioinformatic sequence searching we identified 30 RSH families, and now we work on uncovering the architecture of the ppGpp-mediated cross-talk between various RSH members. Our in vivo single molecule experiments led to the formulation of the ‘extended hopping’ mechanism of RelA’s catalytic cycle.


Our second direction is calorimetric investigations of translational GTPases. Using thermodynamic data obtained in the Isothermal Titration Calorimetry (ITC) experiment, we connect GTPase binding to ligands to the structural rearrangements induced in the protein. We have demonstrated that binding of G nucleotides and initiator tRNA to bacterial Initiation Factor 2 (IF2) are independent of each other whereas binding of the SRL rRNA and GDP to IF2 and GDP are mutually exclusive, that binding of GDP to IF2 promotes significant structural rearrangements, and that complex formation between eukaryotic termination factors eRF1 and eRF3 is independent of eRF3’s interaction with PolyA Binding Protein (PABP).


Our third direction is investigation of the mitochondrial protein biosynthesis and protein import in S. cerevisiae. Using a combination of bioinformatic sequence searching, phylogenetic analysis and genetic analysis, we identified and validated Aim23  as the S. cerevisiae mitochondrial Initiation Factor 3 (mIF3), which was previously deemed missing. By means of single molecule fluorescence microscopy, we analyzed the diffusive properties of the mitochondrial protein import pore TOM40, and demonstrated that it is highly dynamic but spatially confined.


We perform our research in a highly collaborative manner. See the list of our current collaborators here. If you are interested in our past collaborative activities, see our publication list.

 

Research

  

   Contact info

   Address    Vasili Hauryliuk

                       University of Tartu

                       Institute of Technology

                       Nooruse St 1

                       room 400

                       50411 Tartu

                       Estonia

   phone       +372 737 48 45

   Email          vasili.hauryliuk@ut.ee