Press-room / Digest
Screening of the promising direct thrombin inhibitors from haematophagous organisms. Part I: Recombinant analogues and their antithrombotic activity in vitro
This is a collaborative work of researchers from the Laboratory of Biopharmaceutical Technologies of the IBCh RAS and Biological Testing Laboratory of the BIBCh RAS. Its goal is the development and testing of new anticoagulants from haematophagous organisms. Haemadin from the leech Haemadipsa sylvestris, variegin from the tick Amblyomma variegatum, and anophelin from Anopheles albimanus were chosen as the most promising anticoagulants. We have developed a method for the biotechnological production of these recombinant peptides with pharmaceutical purity. As a reference standard, we have used the recombinant hirudin-1 from Hirudo medicinalis (desirudin), which is the active substance of the FDA-approved drug Iprivask (Aventis Pharmaceuticals, USA). The anticoagulant activities of these peptides were compared using the thrombin amidolytic activity assay and detection of the prolongation of coagulation time (thrombin time, prothrombin time, and activated partial thromboplastin time) in mouse and human plasma. The article was published in the journal Biomedicines (IF 6.081).

Comparative Analysis of Enzymatic Transglycosylation Using E.coli Nucleoside Phosphorylases: A Synthetic Concept for the Preparation of Purine Modified 2′-Deoxyribonucleosides from Ribonucleosides
The team of scientists from the Laboratory of Biopharmaceutical Technologies of the IBCh RAS and from the Engelhardt Institute of Molecular Biology (IMB RAS) has developed an efficient method for the preparative synthesis of modified purine 2'-deoxyribonucleosides. For this purpose, a comparative analysis of the conditions of the transglycosylation reaction catalyzed by purine (PNP) and thymidine (TP) nucleoside phosphorylases leading to the formation of 2'-deoxynucleosides, was carried out. It was shown that maximal yields of 2′-deoxyribonucleosides, especially modified, can be achieved under small excess of glycosyl-donor (7-methyl-2'-deoxyguanosine, thymidine) and a 4-fold lack of phosphate. A less than equimolar phosphate concentration allows using only a small excess of the nucleoside-donor of the carbohydrate residue to increase the yield of the reaction. The work was published in the International Journal of Molecular Sciences (IF 5.924).

Capsule-Targeting Depolymerases Derived from Acinetobacter baumannii Prophage Regions
A team of scientists from the Laboratory of molecular bioengineering IBCh RAS together with the colleagues from other Russian Institutes bioinformatically predicted and recombinantly produced several different depolymerases encoded in the prophage regions of Acinetobacter baumannii genomes. For two depolymerases, the specificity to capsular polysaccharides (CPSs) of A. baumannii belonging to K1 and K92 capsular types (K types) was determined. The data obtained showed that the prophage-derived depolymerases were glycosidases that cleaved the A. baumannii CPSs by the hydrolytic mechanism to yield monomers and oligomers of the K units. The recombinant proteins with established enzymatic activity significantly reduced the mortality of Galleria mellonella larvae infected with A. baumannii of K1 and K92 capsular types. These enzymes can be considered as suitable candidates for the development of new antibacterials against corresponding A. baumannii K types. The study is published in the International Journal of Molecular Sciences. Learn more

Evolution of Phage Tail Sheath Protein
Sheath proteins comprise a part of the contractile molecular machinery present in bacteriophages with myoviral morphology, contractile injection systems, and the type VI secretion system (T6SS) found in many Gram-negative bacteria. A team of scientists from the Laboratory of molecular bioengineering IBCh RAS analysed 112 contractile phage tail sheath proteins (TShP) representing different groups of bacteriophages and archaeal viruses with myoviral morphology have been modelled with the novel machine learning software, AlphaFold 2. The common core domain of all studied sheath proteins, including viral and T6SS proteins, comprised both N-terminal and C-terminal parts, whereas the other parts consisted of one or several moderately conserved domains, presumably added during phage evolution. The results are published in the Viruses. Learn more

Heterogeneity of the GFP fitness landscape and data-driven protein design
Understanding the relationship between genotype and phenotype, the fitness landscape, elucidates the fundamental laws of heredity and may ultimately create novel methods of protein design. In the present work a team of scientists from the Group of synthetic biology and the Group of molecular tags for optical nanoscopy IBCh RAS in the collaboration with foreign colleagues combined several approaches to engineer new variants of naturally occurring green fluorescent proteins by generating tens of thousands GFP mutant variants and assessing their ability to fluoresce. Moreover, machine learning algorithms were used for the predicting the performance of other GFP variants and expanding their fitness landscape. The published results indicate that to generate functional protein variants and to predict a protein’s function the algorithm only requires data on the effects of single-site mutations and their dependence on each other (low-order epistasis). The resulrs are published in the eLife journal. Learn more