Biomedical subjects

Sergey G Guryanov

Publications and source records attributed to Sergey G Guryanov.

2 recordsLinked to original sources

PubMed2026

Crystal structures of Parechovirus A1 3Dpol reveal a mechanism of conformational stabilization in +ssRNA virus RNA-dependent RNA polymerase.

Parechovirus A1 (PeV A1) 3Dpol is an RNA-dependent RNA polymerase responsible for replication of the virus genome. We solved crystal structures of PeV A1 3Dpol structure in complex with GTP and in apo-state at 1.8-2.0 Å resolutions. In the 3Dpol-GTP complex, the conformation of the conserved motif B loop was stabilized by zinc ion coordination by cysteine residues. Apo-state structures of PeV A1 3Dpol showed significant conformational flexibility in the motif B loop, in the absence of zinc. While one of the conformational states of apo-3Dpol was similar to the 3Dpol-GTP complex structure, the alternative apo-3Dpol conformation showed a 4.3 Å movement of the motif B loop out of the active site cavity relative to the complex of 3Dpol with GTP. We propose that PeV A1 3Dpol activity is regulated by conformational stabilization of the motif B loop by zinc coordination.

Crystal structure↗

PubMed2005

Proteasome-mediated cleavage of the Y-box-binding protein 1 is linked to DNA-damage stress response.

YB-1 is a DNA/RNA-binding nucleocytoplasmic shuttling protein whose regulatory effect on many DNA- and RNA-dependent events is determined by its localization in the cell. Distribution of YB-1 between the nucleus and the cytoplasm is known to be dependent on nuclear targeting and cytoplasmic retention signals located within the C-terminal portion of YB-1. Here, we report that YB-1 undergoes a specific proteolytic cleavage by the 20S proteasome, which splits off the C-terminal 105-amino-acid-long YB-1 fragment containing a cytoplasmic retention signal. Cleavage of YB-1 by the 20S proteasome in vitro appears to be ubiquitin- and ATP-independent, and is abolished by the association of YB-1 with messenger RNA. We also found that genotoxic stress triggers a proteasome-mediated cleavage of YB-1 in vivo and leads to accumulation of the truncated protein in nuclei of stressed cells. Endoproteolytic activity of the proteasome may therefore play an important role in regulating YB-1 functioning, especially under certain stress conditions.

Adenosine Triphosphate↗