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Title: Crystal structure of phototoxic orange fluorescent proteins with α tryptophan-based chromophore

Phototoxic fluorescent proteins represent a sparse group of genetically encoded photosensitizers that could be used for precise light-induced inactivation of target proteins, DNA damage, and cell killing. Only two such GFP-based fluorescent proteins (FPs), KillerRed and its monomeric variant SuperNova, were described up to date. We present a crystallographic study of their two orange successors, dimeric KillerOrange and monomeric mKiller-Orange, at 1.81 and 1.57 Å resolution, respectively. They are the first orange-emitting protein photosensitizers with a tryptophan-based chromophore (Gln65-Trp66-Gly67). Same as their red progenitors, both orange photosensitizers have a water-filled channel connecting the chromophore to the β-barrel exterior and enabling transport of ROS. In both proteins, Trp66 of the chromophore adopts an unusual trans-cis conformation stabilized by H-bond with the nearby Gln159. This trans-cis conformation along with the water channel was shown to be a key structural feature providing bright orange emission and phototoxicity of both examined orange photosensitizers.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [3] ;  [4] ;  [5]
  1. Russian Academy of Sciences (RAS), Moscow (Russian Federation)
  2. Russian Academy of Sciences (RAS), Moscow (Russian Federation); Moscow State Univ., Moscow (Russian Federation)
  3. Russian Academy of Sciences (RAS), Moscow (Russian Federation); Nizhny Novgorod State Medical Academy, Nizhny Novgorod (Russian Federation)
  4. National Cancer Insitute, Argonne, IL (United States)
  5. National Cancer Insitute, Argonne, IL (United States); Leidos Biomedical Research, Inc., Argonne, IL (United States)
Publication Date:
OSTI Identifier:
1239529
Type:
Accepted Manuscript
Journal Name:
PLoS ONE
Additional Journal Information:
Journal Volume: 10; Journal Issue: 12; Journal ID: ISSN 1932-6203
Publisher:
Public Library of Science
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES