Affiliation:
1. Molecular Biophysics Laboratory Department of Biological Sciences Indian Institute of Science Education and Research Bhopal Bypass Road, Bhauri Bhopal 462066 Madhya Pradesh India
Abstract
AbstractPhoto‐actively modified natural amino acids have served as lucrative probes for precise mapping of the dynamics, interaction networks, and turnover of cytosolic proteins both in vivo and ex vivo. In our attempts to extend the utility of photoreactive reporters to map the molecular characteristics of vital membrane proteins, we carried out site‐selective incorporation of 7‐fluoro‐indole in the human mitochondrial outer membrane protein VDAC2 (voltage‐dependent anion channel isoform 2), with the aim of generating Trp−Phe/Tyr cross‐links. Prolonged irradiation at 282 nm provided us with a surprisingly unusual fluorophore that displayed sizably red‐shifted excitation (λex‐max=280 nm→360 nm) and emission (λem‐max=330 nm→430 nm) spectra that was reversible with organic solvents. By measuring the kinetics of the photo‐activated cross‐linking with a library of hVDAC2 variants, we demonstrate that formation of this unusual fluorophore is kinetically retarded, independent of tryptophan, and is site‐specific. Using other membrane (Tom40 and Sam50) and cytosolic (MscR and DNA Pol I) proteins, we additionally show that formation of this fluorophore is protein‐independent. Our findings reveal the photoradical‐mediated accumulation of reversible tyrosine cross‐links, with unusual fluorescent properties. Our findings have immediate applications in protein biochemistry and UV‐mediated protein aggregation and cellular damage, opening avenues for formulating therapeutics that prolong cell viability in humans.
Funder
The Wellcome Trust DBT India Alliance
Department of Biotechnology, Ministry of Science and Technology, India
Science and Engineering Research Board
Subject
Organic Chemistry,Molecular Biology,Molecular Medicine,Biochemistry
Cited by
1 articles.
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