184591-51-3Relevant articles and documents
Crystal structure of a domain-swapped photoactivatable sfGFP variant provides evidence for GFP folding pathway
Kesgin-Schaefer, Stephanie,Heidemann, Johannes,Puchert, Anke,Koelbel, Knut,Yorke, Briony A.,Huse, Nils,Pearson, Arwen R.,Uetrecht, Charlotte,Tidow, Henning
, p. 2329 - 2340 (2019)
Photoactivatable fluorescent proteins (PA-FPs) are a powerful non-invasive tool in high-resolution live-cell imaging. They can be converted from an inactive to an active form by light, enabling the spatial and temporal trafficking of proteins and cell dynamics. PA-FPs have been previously generated by mutating selected residues in the chromophore or in its close proximity. A new strategy to generate PA-FPs is the genetic incorporation of unnatural amino acids (UAAs) containing photocaged groups using unique suppressor tRNA/aminoacyl-tRNA synthetase pairs. We set out to develop a photoactivatable GFP variant suitable for time-resolved structural studies. Here, we report the crystal structure of superfolder GFP (sfGFP) containing the UAA ortho-nitrobenzyl-tyrosine (ONBY) at position 66 and its spectroscopic characterization. Surprisingly, the crystal structure (to 2.7?? resolution) reveals a dimeric domain-swapped arrangement of sfGFP66ONBY with residues 1–142 of one molecule associating with residues 148–234 from another molecule. This unusual domain-swapped structure supports a previously postulated GFP folding pathway that proceeds via an equilibrium intermediate.
Light activation of staphylococcus aureus toxin YoeBSa 1 reveals guanosine-specific endoribonuclease activity
Larson, Amy S.,Hergenrother, Paul J.
, p. 188 - 201 (2014)
The Staphylococcus aureus chromosome harbors two homologues of the YefM-YoeB toxin-antitoxin (TA) system. The toxins YoeBSa1 and YoeBSa2 possess ribosome-dependent ribonuclease (RNase) activity in Escherichia coli. This activity is similar to that of the E. coli toxin YoeBEc, an enzyme that, in addition to ribosome-dependent RNase activity, possesses ribosome-independent RNase activity in vitro. To investigate whether YoeBSa1 is also a ribosome-independent RNase, we expressed YoeBSa1 using a novel strategy and characterized its in vitro RNase activity, sequence specificity, and kinetics. Y88 of YoeBSa1 was critical for in vitro activity and cell culture toxicity. This residue was mutated to o-nitrobenzyl tyrosine (ONBY) via unnatural amino acid mutagenesis. YoeBSa1-Y88ONBY could be expressed in the absence of the antitoxin YefMSa1 in E. coli. Photocaged YoeBSa1-Y88ONBY displayed UV light-dependent RNase activity toward free mRNA in vitro. The in vitro ribosome-independent RNase activity of YoeBSa1-Y88ONBY, YoeB Sa1-Y88F, and YoeBSa1-Y88TAG was significantly reduced or abolished. In contrast to YoeBEc, which cleaves RNA at both adenosine and guanosine with a preference for adenosine, YoeBSa1 cleaved mRNA specifically at guanosine. Using this information, a fluorometric assay was developed and used to determine the kinetic parameters for ribosome-independent RNA cleavage by YoeBSa1.
Site-specific incorporation of fluorotyrosines into proteins in escherichia coli by photochemical disguise
Wilkins, Bryan J.,Marionni, Samue,Young, Douglas D.,Liu, Jia,Wang, Yan,Di Salvo, Martino L.,Deiters, Alexander,Cropp, T. Ashton
scheme or table, p. 1557 - 1559 (2011/01/12)
Fluorinated analogues of tyrosine can be used to manipulate the electronic environments of protein active sites. The ability to selectively mutate tyrosine residues to fluorotyrosines is limited, however, and can currently only be achieved through the tot
