Biology subjects

Pichova, I.

Publications and source records attributed to Pichova, I..

3 recordsLinked to original sources

bioRxiv2021

The mycobacterial guaB1 gene encodes a guanosine 5'-monophosphate reductase with a cystathione-β-synthase domain

Purine metabolism plays a pivotal role in bacterial life cycle, however, regulation of the de novo and purine salvage pathways have not been extensively detailed in mycobacteria. By gene knockout, biochemical and structural analyses, we identified Mycobacterium smegmatis (Msm) and Mycobacterium tuberculosis (Mtb) guaB1 gene product as a novel type of guanosine 5-monophosphate reductase (GMPR), which recycles guanosine monophosphate to inosine monophosphate within the purine salvage pathway and contains cystathione {beta}-synthase (CBS) domains with atypical orientation in the octamer. CBS domains share a much larger interacting area with a conserved catalytic domain in comparison with the only known CBS containing protozoan GMPR and closely related inosine monophosphate dehydrogenase structures. Our results revealed essential effect of pH on allosteric regulation of Msm GMPR activity and oligomerization with adenine and guanosine nucleotides binding to CBS domains.Bioinformatic analysis indicated the presence of GMPRs containing CBS domains across the entire Actinobacteria phylum.

biochemistry↗

bioRxiv2021

Biogenesis of hepatitis B virus e antigen is driven by translocon-associated protein complex and regulated by conserved cysteines in signal peptide

Hepatitis B virus (HBV) uses e antigen (HBe), which is dispensable for virus infectivity, to modulate host immune responses and achieve viral persistence in human hepatocytes. The HBe precursor (p25) is directed to the endoplasmic reticulum (ER), where cleavage of the signal peptide (sp) gives rise to the first processing product, p22. P22 can be retro-translocated back to the cytosol or enter the secretory pathway and undergo a second cleavage event, resulting in secreted p17 (HBe). Here, we report that translocation of p25 to the ER is promoted by translocon-associated protein complex (TRAP). We found that p25 is not completely translocated into the ER; a fraction of p25 is phosphorylated and remains in the cytoplasm and nucleus. Within the p25 sp sequence, we identified three cysteine residues that control the efficiency of sp cleavage and contribute to proper subcellular distribution of the precore pool.

cell biology↗

bioRxiv2018

Expansion of the fatty acyl reductase gene family shaped pheromone communication in Hymenoptera

The conserved fatty acyl reductase (FAR) family is involved in biosynthesis of fatty alcohols that serve a range of biological roles. In moths, butterflies (Lepidoptera), and bees (Hymenoptera), FARs biosynthesize fatty alcohol pheromones participating in mate-finding strategies. Using a combination of next-generation sequencing, analysis of transposable elements (TE) in the genomic environment of FAR genes, and functional characterization of FARs from Bombus lucorum, B. lapidarius, and B. terrestris, we uncovered a massive expansion of the FAR gene family in Hymenoptera, presumably facilitated by TEs. Expansion occurred in the common ancestor of bumblebees (Bombini) and stingless bees (Meliponini) after their divergence from the honeybee lineage. We found that FARs from the expanded FAR-A orthology group contributed to the species-specific male marking pheromone composition. Our results indicate that TE-mediated expansion and functional diversification of the FAR gene family played a key role in the evolution of pheromone communication in the crown group of Hymenoptera.\n\nAbbreviationsMMP: male marking pheromone, FA: fatty acid, FAME: fatty acid methyl ester, FAR: fatty acyl reductase, LG: labial gland, FB: fat body, TE: transposable element.

evolutionary biology↗