On the Case of the Misplaced Hydrogens

Area of Science:

• Biochemistry
• Structural Biology
• Biophysics

Background:

• Hydrogen atoms are fundamental to biological structure and function, particularly in catalysis and molecular interactions.
• Short hydrogen bonds (SHBs) are critical but challenging to study due to the difficulty in precisely locating hydrogen atoms.
• The precise role of SHBs in biological systems remains debated, leading to inconsistencies in research findings.

Purpose of the Study:

• To investigate the precise location and role of hydrogen atoms within short hydrogen bonds (SHBs) in biological systems.
• To resolve the ongoing debate regarding the significance of SHBs in protein chemistry and stability.
• To provide a contextual understanding of SHB function through detailed analysis of specific protein examples.

Main Methods:

• Utilizing advanced experimental and computational techniques to precisely determine hydrogen atom locations.
• Analyzing the energetic contributions of SHBs, ranging from canonical to single-well hydrogen bonds.
• Examining two distinct biological systems: a conserved catalytic triad and the photoactive yellow protein.

Main Results:

• Demonstrated that the precise location of hydrogen atoms in SHBs is indicative of bond strength, varying from 1-5 kcal/mol.
• Provided clear evidence for the functional importance of SHBs in the studied protein systems.
• Resolved discrepancies between computational, biochemical, and structural studies concerning SHB involvement.

Conclusions:

• The precise determination of hydrogen atom positions is key to understanding SHB function in biology.
• SHBs play a significant, context-dependent role in protein catalysis and stabilization.
• This work contextualizes the importance of SHBs, resolving previous scientific debates and discrepancies.