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Igor V Yaminsky

Publications and source records attributed to Igor V Yaminsky.

4 recordsLinked to original sources
PubMed2004

Structural organization of mRNA complexes with major core mRNP protein YB-1.

YB-1 is a universal major protein of cytoplasmic mRNPs, a member of the family of multifunctional cold shock domain proteins (CSD proteins). Depending on its amount on mRNA, YB-1 stimulates or inhibits mRNA translation. In this study, we have analyzed complexes formed in vitro at various YB-1 to mRNA ratios, including those typical for polysomal (translatable) and free (untranslatable) mRNPs. We have shown that at mRNA saturation with YB-1, this protein alone is sufficient to form mRNPs with the protein/RNA ratio and the sedimentation coefficient typical for natural mRNPs. These complexes are dynamic structures in which the protein can easily migrate from one mRNA molecule to another. Biochemical studies combined with atomic force microscopy and electron microscopy showed that mRNA-YB-1 complexes with a low YB-1/mRNA ratio typical for polysomal mRNPs are incompact; there, YB-1 binds to mRNA as a monomer with its both RNA-binding domains. At a high YB-1/mRNA ratio typical for untranslatable mRNPs, mRNA-bound YB-1 forms multimeric protein complexes where YB-1 binds to mRNA predominantly with its N-terminal part. A multimeric YB-1 comprises about twenty monomeric subunits; its molecular mass is about 700 kDa, and it packs a 600-700 nt mRNA segment on its surface.

Animals↗
PubMed2003

AFM study of potato virus X disassembly induced by movement protein.

Recently we have reported that a selective binding of potato virus X (PVX)-coded movement protein (termed TGBp1 MP) to one end of a polar coat protein (CP) helix converted viral RNA into a translatable form and induced a linear destabilization of the whole helical particle. Here, the native PVX virions, RNase-treated (PVX(RNA-DEG)) helical particles lacking intact RNA and their complexes with TGBp1 (TGBp1-PVX and TGBp1-PVX(RNA-DEG)), were examined by atomic force microscopy (AFM). When complexes of the TGBp1 MP with PVX were examined by means of AFM in liquid, no structural reorganization of PVX particles was observed. By contrast, the products of TGBp1-dependent PVX degradation termed "beads-on-string" were formed under conditions of AFM in air. The AFM images of PVX(RNA-DEG) were indistinguishable from images of native PVX particles; however, the TGBp1-dependent disassembly of the CP-helix was triggered when the TGBp1-PVX(RNA-DEG) complexes were examined by AFM, regardless of the conditions used (in air or in liquid). Our data supported the idea that binding of TGBp1 to one end of the PVX CP-helix induced linear destabilization of the whole helical particle, which may lead to its disassembly under conditions of AFM.

Capsid Proteins↗
PubMedDate not supplied

Microbial surfaces investigated using atomic force microscopy.

This paper is dedicated to atomic force microscopy (AFM) as a progressive tool for imaging bacterial surfaces and probing their properties. The description of the technique is complemented by the explanation of the method's artifacts typical, in particular, for the imaging of bacterial cells. Sample preparation techniques are summarized in a separate section. Special attention is paid to the differences in imaging of gram-positive and gram-negative bacteria. Probing of mechanical properties, including elastic modulus, fragility, and adhesion of the cell walls is emphasized. The advantages of AFM in the studies of real-time cellular dynamical processes are illustrated by the experiment with the germination of spores.

Bacteria↗