Effect of pH on the activity of ice-binding protein from Marinomonas primoryensis

Area of Science:

• Biochemistry
• Materials Science
• Protein Engineering

Background:

• Ice-binding proteins (IBPs) are crucial for organisms in cold environments.
• Understanding IBP function under non-physiological conditions is vital for biotechnological applications.
• Marinomonas primoryensis ice-binding protein (MpIBP) is a potential candidate for such studies.

Purpose of the Study:

• To investigate the ice-binding and ice-shaping capabilities of MpIBP in non-physiological pH environments.
• To determine the stability of MpIBP's secondary structure across a range of pH values.
• To assess the potential of MpIBP for materials science and engineering applications.

Main Methods:

• Modified splat assay to measure ice recrystallization inhibition (IRI).
• Nanoliter osmometry to evaluate dynamic ice shaping (DIS).
• Circular dichroism (CD) spectroscopy to analyze protein secondary structure.

Main Results:

• MpIBP retained stable secondary structure between pH 6 and pH 10.
• MpIBP showed reduced ice crystal grain size from pH 6 to 12.
• Dynamic ice shaping was observed between pH 6 and 10, with no interaction at pH ≤ 4 or ≥ 13.

Conclusions:

• MpIBP exhibits significant ice-binding and ice-shaping activity in non-neutral pH environments.
• The protein maintains functional secondary structure under stressed pH conditions.
• MpIBP demonstrates potential for use in materials science and engineering applications requiring ice modulation.