Photoprogramming Allostery in Human Serum Albumin

Area of Science:

• Biochemistry
• Molecular Biology
• Biophysics

Background:

• Allosteric interactions in proteins are crucial for cellular processes.
• External triggers are sought for precise regulation of these interactions.
• Light offers spatiotemporal selectivity and physiological compatibility as a trigger.

Purpose of the Study:

• To engineer a hybrid protein with light-controlled allosteric communication.
• To investigate optical regulation of ligand binding in human serum albumin.
• To demonstrate photoprogramming of protein binding activities.

Main Methods:

• Covalent incorporation of a synthetic photoswitch into human serum albumin (HSA) subdomain IA.
• Experimental characterization of light-induced changes in ligand binding at subdomain IB.
• Molecular dynamics (MD) simulations to confirm allosteric communication and mechanism.

Main Results:

• Engineered HSA exhibits light-inducible allosteric control over ligand binding.
• Illumination triggers photoswitch photoconversion, altering inter-subdomain dynamics (IA and IB).
• Increased flexibility in subdomain IB's binding pocket facilitates ligand release upon light exposure.

Conclusions:

• Artificial molecular switches can be harnessed to introduce photoprogrammable allosteric regulation.
• This strategy enables optical control of binding activities in prominent proteins like HSA.
• The engineered system deepens understanding of allosteric mechanisms and offers novel regulatory tools.