8DB2

Q108K:K40L:T51C:T53A:R58L:Q38F mutant of hCRBPII bound to synthetic fluorophore CM1V

Summary for 8DB2

• Entry DOI: 10.2210/pdb8db2/pdb
• Descriptor: Retinol-binding protein 2, (2E)-3-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]prop-2-enal, bound form (3 entities in total)
• Functional Keywords: hcrbpii, transport protein
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 1
• Total formula weight: 15786.83

Authors

Bingham, C.R.,Geiger, J.H.,Borhan, B.,Staples, R. (deposition date: 2022-06-14, release date: 2023-02-01, Last modification date: 2023-10-25)

Primary citation

Maity, S.,Bingham, C.,Sheng, W.,Ehyaei, N.,Chakraborty, D.,Tahmasebi-Nick, S.,Kimmel, T.E.,Vasileiou, C.,Geiger, J.H.,Borhan, B.
Light controlled reversible Michael addition of cysteine: a new tool for dynamic site-specific labeling of proteins.
Analyst, 148:1085-1092, 2023

PubMed Abstract: Cysteine-based Michael addition is a widely employed strategy for covalent conjugation of proteins, peptides, and drugs. The covalent reaction is irreversible in most cases, leading to a lack of control over the process. Utilizing spectroscopic analyses along with X-ray crystallographic studies, we demonstrate Michael addition of an engineered cysteine residue in human Cellular Retinol Binding Protein II (hCRBPII) with a coumarin analog that creates a non-fluorescent complex. UV-illumination reverses the conjugation, yielding a fluorescent species, presumably through a -Michael process. This series of events can be repeated between a bound and non-bound form of the cysteine reversibly, resulting in the ON-OFF control of fluorescence. The details of the mechanism of photoswitching was illuminated by recapitulation of the process in light irradiated single crystals, confirming the mechanism at atomic resolution.

PubMed: 36722993
DOI: 10.1039/d2an01395a

Experimental method

X-RAY DIFFRACTION (1.5 Å)