https://doi.org/10.5061/dryad.f4qrfj7b4

Dataset Overview

This repository contains raw small-angle X-ray scattering (SAXS) data acquired at the BioSAXS beamline (ID7A1) at the Cornell High Energy Synchrotron Source (CHESS).

The data support the manuscript:

"The Role of the 2'-OH Group in Phase Separation and Percolation Transitions of RNA."

Experiments were designed to investigate the effects of sequence, repeat length, temperature, and magnesium concentration on the conformational behavior of RNA and single-stranded DNA (ssDNA).

Raw detector data are provided as HDF5 files together with SAXS reporting tables and metadata required to reproduce data reduction and analysis workflows.

Directory Structure

1st_visit.zip/
├── 1st visit/
│   ├── rCAG31/
│   ├── dCAG31/
│   ├── Buffer/
│   ├── Water/
│   ├── empty/
│   ├── setup files/
│   └── averages and subtracted profiles/
│
├── 2nd visit/
│   ├── rCAG31/
│   ├── dCAG31/
│   ├── rCAG6/
│   ├── dCAG6/
│   ├── rCUU31/
│   ├── dCTT31/
│   ├── ion titrations/
│   ├── Buffer/
│   ├── water/
│   ├── empty cell/
│   └── setup file/
│
└── 3rd visit/
    ├── rCAG31 - 10mM Mg/
    ├── dCAG31 - 10mM Mg/
    ├── rCUU31 - 10mM Mg/
    ├── dCTT31 - 10mM Mg/
    ├── rCAG6 concentration titration/
    ├── dCAG6 concentration titration/
    ├── Buffer/
    ├── Water/
    ├── Empty cell/
    └── setup files/

Each visit folder contains an additional README file describing the specific experimental conditions used during that beamtime.

File Naming Convention

Files are named according to the following format:

<sequence><repeat length><Na concentration><Mg concentration>_<temperature>

For example:

rCAG311010_37degC

indicates:

• Sequence: rCAG
• Repeat length: 31
• Na concentration: 10 mM
• Mg concentration: 10 mM
• Temperature: 37 °C

Sequence abbreviations:

• rCAG: RNA CAG repeat
• dCAG: ssDNA CAG repeat
• rCUU: RNA CUU repeat
• dCTT: ssDNA CTT repeat

Temperature suffixes correspond to the acquisition temperature in degrees Celsius.

Experimental Conditions

Unless otherwise specified in the folder-specific README files:

• Buffer: 50 mM HEPES, pH 7.5
• NaCl: 10 mM
• MgCl₂: variable (1–10 mM depending on experiment)
• Nucleic acid concentrations: specified in folder names and README files

Experiments include:

• Temperature-dependent SAXS measurements
• Magnesium titrations
• Concentration titrations
• Independent replicate measurements across multiple CHESS visits

Buffer-only, water standard, and empty-cell measurements are provided for background subtraction and instrument calibration.

Raw Data Files

HDF5 files contain the original detector data acquired at CHESS ID7A1.

Each acquisition typically consists of multiple 1 s exposures collected sequentially.

Additional metadata embedded within the HDF5 files include:

• Beamline configuration
• Detector information
• Exposure times
• X-ray wavelength
• Sample temperature
• Acquisition timestamps

Data reduction and analysis were performed using BioXTAS RAW as described in the associated manuscript.

Supporting Documentation

This repository also includes:

• SAXS reporting tables
• Visit-specific README files
• Experimental setup files
• Buffer compositions
• Calibration measurements (water standards)

Beamline Information

• Facility: Cornell High Energy Synchrotron Source (CHESS)
• Beamline: ID7A1 BioSAXS
• Detector: Dectris Eiger 4M
• Wavelength: 1.11365 Å
• Photon energy: 11.13 keV

Contact Information

Questions regarding this dataset should be directed to the corresponding authors listed in the associated manuscript.