Magnetic properties and structure of oxyhemoglobin

Area of Science:

• Biophysics
• Biochemistry
• Physical Chemistry

Background:

• The magnetic properties of hemoglobin are crucial for understanding its function.
• Previous research, including Pauling and Coryell (1936), suggested oxyhemoglobin has no magnetic moment at physiological temperatures.
• Recent studies have proposed contradictory findings based on low-temperature magnetic susceptibility measurements.

Purpose of the Study:

• To review existing evidence regarding the magnetic moment of oxyhemoglobin.
• To address discrepancies in reported magnetic susceptibility data for oxyhemoglobin.
• To provide theoretical predictions for molecular geometry in hemoglobin derivatives.

Main Methods:

• Literature review of published evidence on oxyhemoglobin magnetic properties.
• Analysis of magnetic susceptibility data from various studies, including low-temperature experiments.
• Computational prediction of bond lengths and angles for carbonmonoxyhemoglobin and oxyhemoglobin.

Main Results:

• The review reinforces the 1936 conclusion that oxyhemoglobin in blood or solution at 20°C exhibits zero magnetic moment.
• Evidence does not support recent claims based on magnetic susceptibility of frozen samples below 250 K.
• Predicted values for bond lengths and angles in carbonmonoxyhemoglobin and oxyhemoglobin are presented.

Conclusions:

• The magnetic moment of oxyhemoglobin at physiological temperatures is definitively zero.
• The interpretation of magnetic susceptibility data from frozen samples requires careful consideration of temperature effects.
• Theoretical calculations provide structural insights into hemoglobin-ligand interactions.