Open AccessChoosing the right label for single-molecule tracking in live bacteria: side-by-side comparison of photoactivatable fluorescent protein and Halo tag dyes
Author(s) -
Nehir Banaz,
Jarno Mäkelä,
Stephan Uphoff
Publication year - 2018
Publication title -
journal of physics. d, applied physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.857
H-Index - 198
eISSN - 1361-6463
pISSN - 0022-3727
DOI - 10.1088/1361-6463/aaf255
Subject(s) - fluorescence , labelling , photobleaching , fluorescence microscope , biophysics , chemistry , microscopy , protein tag , bimolecular fluorescence complementation , fluorescent protein , fluorescence recovery after photobleaching , super resolution microscopy , green fluorescent protein , biochemistry , biology , optics , physics , gene , fusion protein , recombinant dna
Visualizing and quantifying molecular motion and interactions inside living cells provides crucial insight into the mechanisms underlying cell function. This has been achieved by super-resolution localization microscopy and single-molecule tracking in conjunction with photoactivatable fluorescent proteins (PA-FPs). An alternative labelling approach relies on genetically-encoded protein tags with cell-permeable fluorescent ligands which are brighter and less prone to photobleaching than fluorescent proteins but require a laborious labelling process. Either labelling method is associated with significant advantages and disadvantages that should be taken into consideration depending on the microscopy experiment planned. Here, we describe an optimised procedure for labelling Halo-tagged proteins in live Escherichia coli cells. We provide a side-by-side comparison of Halo tag with different fluorescent ligands against the popular photoactivatable fluorescent protein PAmCherry. Using test proteins with different intracellular dynamics, we evaluated fluorescence intensity, background, photostability, and results from single-molecule localization and tracking experiments. Capitalising on the brightness and extended spectral range of fluorescent Halo ligands, we also demonstrate high-speed and dual-colour single-molecule tracking.