A New-Generation Fluorescent-Based Metal Sensor – iLOV Protein

Yuvaraj Ravikumar, Saravanan Prabhu Nadarajan, Chong Soon Lee, Jin Kyu Rhee, Hyungdon Yun

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

The iLOV protein belongs to a family of blue-light photoreceptor proteins containing a lightoxygen- voltage sensing domain with a noncovalently bound flavin mononucleotide (FMN) as its chromophore. Owing to advantages such as its small size, oxygen-independent nature, and pH stability, iLOV is an ideal candidate over other reporter fluorescent proteins such as GFP and DsRed. Here, for the first time, we describe the feasibility of applying LOV domain-based fluorescent iLOV as a metal sensor by measuring the fluorescence quenching of a protein with respect to the concentration of metal ions. In the present study, we demonstrated the inherent copper sensing property of the iLOV protein and identified the possible amino acids responsible for metal binding. The fluorescence quenching upon exposure to Cu2++ was highly sensitive and exhibited reversibility upon the addition of the metal chelator EDTA. The copper binding constant was found to be 4.72 ± 0.84 μM. In addition, Cu2+-bound iLOV showed high fluorescence quenching at near physiological pH. Further computational analysis yielded a better insight into understanding the possible amino acids responsible for Cu2++ binding with the iLOV protein.

Original languageEnglish
Pages (from-to)503-510
Number of pages8
JournalJournal of Microbiology and Biotechnology
Volume25
Issue number4
DOIs
StatePublished - 2015

Keywords

  • Copper
  • Fluorescence quenching
  • iLOV protein
  • Metal sensor

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