[Hydratation of the rubredoxin polypeptide chain from data on the spatial structure]

Area of Science:

• Biophysics
• Structural Biology
• Protein Chemistry

Context:

• High-resolution crystal data of rubredoxin was utilized.
• Analysis focused on nearest neighbor atoms around peptide group N and O atoms.
• Hydrogen bond forming atoms were the primary subjects of investigation.

Purpose:

• To analyze the hydration water distribution around the main chain of the protein rubredoxin.
• To understand the principles governing peptide group hydration.
• To propose a method for evaluating main chain hydration.

Summary:

• Approximately 27% of peptide N-H and 53% of peptide C=O groups in rubredoxin are hydrated.
• Hydration follows the principle of maximum in situ hydrogen bond saturation.
• Peptide groups involved in internal hydrogen bonds are generally not hydrated, affecting specific protein regions.

Impact:

• Provides insights into protein hydration mechanisms and water-protein interactions.
• Identifies specific regions of rubredoxin (pleated sheet, loops, Fe-pocket) that are not hydrated.
• Proposes a novel method for assessing protein main chain hydration using atomic coordinates.