Year: 2011
Type: article
Abstract: Single-stranded RNAs (ssRNAs) longer than a few hundred nucleotides do not have a unique structure in solution. Their equilibrium properties therefore reflect the average of an ensemble of structures. We use cryo-electron microscopy to image projections of individual long ssRNA molecules and characterize the anisotropy of their ensembles in solution. A flattened prolate volume is found to best represent the shapes of these ensembles. The measured sizes and anisotropies are in good agreement with complementary determinations using small-angle X-ray scattering and coarse-grained molecular dynamics simulations. A long viral ssRNA is compared with shorter noncoding transcripts to demonstrate that prolate geometry and flatness are generic properties independent of sequence length and origin. The anisotropy persists under physiological as well as low-ionic-strength conditions, revealing a direct correlation between secondary structure asymmetry and 3D shape and size. We discuss the physical origin of the generic anisotropy and its biological implications.
Source: RNA
Authors: Ajaykumar Gopal, Z. Hong Zhou, Charles M. Knobler, William M. Gelbart
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: bronze
Funders: National Science Foundation, U.S. Department of Energy, Nepal Academy of Science and Technology, National Institutes of Health, National Institute of General Medical Sciences, National Center for Research Resources, Division of Chemistry, Basic Energy Sciences, Biological and Environmental Research
OpenAlex ID: W2115586221