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Size, shape, and flexibility of RNA structures

Biomolecules · Submitted 23 Sep 2006

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim Using the coordinates of the structures of RNA in the Protein Data Bank we find that the size of the folded RNA structures, measured using the radius of gyration, $R_G$, follows the Flory scaling law, namely, $R_G =5.5 N^{1/3}$ \AA where N is the number of nucleotides.

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arXiv IDq-bio/0609035 (version 1)
Pith IDDHQKT6L6, Pith's permanent record of this paper and its review
CitationChangbong Hyeon, D. Thirumalai, Ruxandra I. Dima. "Size, shape, and flexibility of RNA structures." arXiv:q-bio/0609035 (2006). https://pith.science/paper/DHQKT6L6
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What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.06 · human participants 0.01 · controlled comparison 0.15 · randomized assignment 0.01 · states quantitative result 0.99 · compares with prior results 0.21 · mentions code or data availability 0.02.

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arXiv listing abstract v1. Results and the main claim are underlined; .

Determination of sizes and flexibilities of RNA molecules is important in understanding the nature of packing in folded structures and in elucidating interactions between RNA and DNA or proteins. Using the coordinates of the structures of RNA in the Protein Data Bank we find that the size of the folded RNA structures, measured using the radius of gyration, $R_G$, follows the Flory scaling law, namely, $R_G =5.5 N^{1/3}$ \AA where N is the number of nucleotides. The shape of RNA molecules is characterized by the asphericity $\Delta$ and the shape $S$ parameters that are computed using the eigenvalues of the moment of inertia tensor. From the distribution of $\Delta$, we find that a large fraction of folded RNA structures are aspherical and the distribution of $S$ values shows that RNA molecules are prolate ($S>0$). The flexibility of folded structures is characterized by the persistence length $l_p$. By fitting the distance distribution function $P(r)$ to the worm-like chain model we extracted the persistence length $l_p$. We find that $l_p\approx 1.5 N^{0.33}$ \AA. The dependence of $l_p$ on $N$ implies the average length of helices should increases as the size of RNA grows. We also analyze packing in the structures of ribosomes (30S, 50S, and 70S) in terms of $R_G$, $\Delta$, $S$, and $l_p$. The 70S and the 50S subunits are more spherical compared to most RNA molecules. The globularity in 50S is due to the presence of an unusually large number (compared to 30S subunit) of small helices that are stitched together by bulges and loops. Comparison of the shapes of the intact 70S ribosome and the constituent particles suggests that folding of the individual molecules might occur prior to assembly.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 Determination of sizes and flexibilities of RNA molecules is important in understanding the nature of packing in folded structures and in elucidating interactions between RNA and DNA or proteins. background 1.00 0.05 0.04 asserted 1.00
s1 Using the coordinates of the structures of RNA in the Protein Data Bank we find that the size of the folded RNA structures, measured using the radius of gyration, $R_G$, follows the Flory scaling law, namely, $R_G =5.5 N^{1/3}$ \AA where N is the number of nucleotides. result 0.98 0.96 0.25 asserted 1.00
s2 The shape of RNA molecules is characterized by the asphericity $\Delta$ and the shape $S$ parameters that are computed using the eigenvalues of the moment of inertia tensor. method 0.98 0.46 0.04 asserted 1.00
s3 From the distribution of $\Delta$, we find that a large fraction of folded RNA structures are aspherical and the distribution of $S$ values shows that RNA molecules are prolate ($S>0$). result 1.00 0.95 0.12 asserted 1.00
s4 The flexibility of folded structures is characterized by the persistence length $l_p$. method 0.89 0.19 0.04 asserted 1.00
s5 By fitting the distance distribution function $P(r)$ to the worm-like chain model we extracted the persistence length $l_p$. method 1.00 0.95 0.03 asserted 1.00
s6 We find that $l_p\approx 1.5 N^{0.33}$ \AA. result 1.00 0.97 0.17 asserted 0.99
s7 The dependence of $l_p$ on $N$ implies the average length of helices should increases as the size of RNA grows. interpretation 1.00 0.75 0.14 hedged possibility 0.59
s8 We also analyze packing in the structures of ribosomes (30S, 50S, and 70S) in terms of $R_G$, $\Delta$, $S$, and $l_p$. contribution 0.95 0.95 0.05 asserted 0.93
s9 The 70S and the 50S subunits are more spherical compared to most RNA molecules. result 1.00 0.91 0.09 asserted 1.00
s10 The globularity in 50S is due to the presence of an unusually large number (compared to 30S subunit) of small helices that are stitched together by bulges and loops. interpretation 0.86 0.87 0.07 asserted 1.00
s11 Comparison of the shapes of the intact 70S ribosome and the constituent particles suggests that folding of the individual molecules might occur prior to assembly. interpretation 0.99 0.84 0.16 hedged possibility 0.58

What kind of paper the classifier reports this is: empirical study 0.90 · evidence from analysis of existing data 0.99.

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The paper
Original abstract

Determination of sizes and flexibilities of RNA molecules is important in understanding the nature of packing in folded structures and in elucidating interactions between RNA and DNA or proteins. Using the coordinates of the structures of RNA in the Protein Data Bank we find that the size of the folded RNA structures, measured using the radius of gyration, $R_G$, follows the Flory scaling law, namely, $R_G =5.5 N^{1/3}$ \AA where N is the number of nucleotides. The shape of RNA molecules is characterized by the asphericity $\Delta$ and the shape $S$ parameters that are computed using the eigenvalues of the moment of inertia tensor. From the distribution of $\Delta$, we find that a large fraction of folded RNA structures are aspherical and the distribution of $S$ values shows that RNA molecules are prolate ($S>0$). The flexibility of folded structures is characterized by the persistence length $l_p$. By fitting the distance distribution function $P(r)$ to the worm-like chain model we extracted the persistence length $l_p$. We find that $l_p\approx 1.5 N^{0.33}$ \AA. The dependence of $l_p$ on $N$ implies the average length of helices should increases as the size of RNA grows. We also analyze packing in the structures of ribosomes (30S, 50S, and 70S) in terms of $R_G$, $\Delta$, $S$, and $l_p$. The 70S and the 50S subunits are more spherical compared to most RNA molecules. The globularity in 50S is due to the presence of an unusually large number (compared to 30S subunit) of small helices that are stitched together by bulges and loops. Comparison of the shapes of the intact 70S ribosome and the constituent particles suggests that folding of the individual molecules might occur prior to assembly.

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