Bujnicki lab - tRNA modification enzyme MiaE
  • RNA has recently emerged as an attractive target for new drug development. Our team is developing new methods to study the interactions between RNA and ligands. Recently, we have developed a new machine learning method called AnnapuRNA to predict how small chemical molecules interact with structured RNA molecules. Research published in PLoS Comput Biol. 2021 Feb 1;17(2):e1008309. doi: 10.1371/journal.pcbi.1008309. Read More
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About Laboratory Of Bioinformatics And Protein Engineering

Our group is involved in theoretical and experimental research on nucleic acids and proteins. The current focus is on RNA sequence-structure-function relationships (in particular 3D modeling), RNA-protein complexes, and enzymes acting on RNA.
 
We study the rules that govern the sequence-structure-function relationships in proteins and nucleic acids and use the acquired knowledge to predict structures and functions for uncharacterized gene products, to alter the known structures and functions of proteins and RNAs and to engineer molecules with new properties.
 
Our key strength is in the integration of various types of theoretical and experimental analyses. We develop and use computer programs for modeling of protein three-dimensional structures based on heterogenous, low-resolution, noisy and ambivalent experimental data. We are also involved in genome-scale phylogenetic analyses, with the focus on identification of proteins that belong to particular families. Subsequently, we characterize experimentally the function of the most interesting new genes/proteins identified by bioinformatics. We also use theoretical predictions to guide protein engineering, using rational and random approaches. Our ultimate goal is to identify complete sets of enzymes involved in particular metabolic pathways (e.g. RNA modification, DNA repair) and to design proteins with new properties, in particular enzymes with new useful functions, which have not been observed in the nature.
 
We are well-equipped with respect to both theoretical and experimental analyses. Our lab offers excellent environment for training of young researchers in both bioinformatics and molecular biology/biochemistry of protein-nucleic acid interactions.


More Good Science

Model of MiaE.
 
MiaE is a hydroxylase responsible for introducing posttranscriptional modification in position 37 in tRNA. The hydroxylation of the i6 group leads to appearance of hypermodification N6-(cis-4-hydroxyi-sopentenyl)-2-thiomethyladenosine (ms2io6A, also called 2-methyltio-cis- ribozeatin) and this process is dependent on the presence of the molecular oxygen (O2). For MiaE, we confidently predict that it shares the three-dimensional fold with the ferritin- like four-helix bundle proteins and that it has a similar active site and mechanism of action to diiron carboxylate enzymes, in particular, methane monooxygenase (E.C.1.14.13.25) that catalyses the biological hydroxylation of alkanes. The crystal structure of PpMiaE (Pseudomonas putida) was published [2] giving us a possibility for direct comparison of our model of StMiaE (Salmonella typhimurium) [1] with the native structure. Our modeling appeared to be very successful and predicted correct protein topology and reviled the structure of regions which were not present in a crystal structure of native protein.

References: 
1. Kaminska KH, Baraniak U, Boniecki M, Nowaczyk K, Czerwoniec A, Bujnicki JM. Structural bioinformatics analysis of enzymes involved in the biosynthesis pathway of the hypermodified nucleoside ms(2)io(6)A37 in tRNA. Proteins. 2008 Jan 1;70(1):1-18. 
2. Joint Center for Structural Genomics (JCSG). Crystal structure of putative tRNA-(ms(2)io(6)a)-hydroxylase (NP_744337.1) from Pseudomonas putida KT2440 at 2.05 A resolution. To be published.

Download structures:
StMiaE model
Native structure of PpMiaE - 2ITB

Read our manuscript:
Download PDF 

Gallery:


Comparison of structures of our model and the native structure (PDB code: 2ITB). Structures are colored according to the sequence index (N-terminus - blue, C-terminus - red). The model is of very good quality in regions of catalytic core. 


Regions with corresponding secondary structure elements are colored in the same way. The structure of regions which were not present in native protein are colored in a dark gray. 


Correctly predicted and functionally important residues of StMiaE. The diiron cluster in StMiaE is shown as gold spheres. Catalytic residues (E59, E137, H140, E190, E219 and H222) are colored in red.