scholarly journals Designing Red-Shifted Molecular Emitters Based on the Annulated Locked GFP Chromophore Derivatives

2021 ◽  
Vol 22 (24) ◽  
pp. 13645
Author(s):  
Gregory D. Sinenko ◽  
Dilara A. Farkhutdinova ◽  
Ivan N. Myasnyanko ◽  
Nadezhda S. Baleeva ◽  
Mikhail S. Baranov ◽  
...  

Bioimaging techniques require development of a wide variety of fluorescent probes that absorb and emit red light. One way to shift absorption and emission of a chromophore to longer wavelengths is to modify its chemical structure by adding polycyclic aromatic hydrocarbon (PAH) fragments, thus increasing the conjugation length of a molecule while maintaining its rigidity. Here, we consider four novel classes of conformationally locked Green Fluorescent Protein (GFP) chromophore derivatives obtained by extending their aromatic systems in different directions. Using high-level ab initio quantum chemistry calculations, we show that the alteration of their electronic structure upon annulation may unexpectedly result in a drastic change of their fluorescent properties. A flip of optically bright and dark electronic states is most prominent in the symmetric fluorene-based derivative. The presence of a completely dark lowest-lying excited state is supported by the experimentally measured extremely low fluorescence quantum yield of the newly synthesized compound. Importantly, one of the asymmetric modes of annulation provides a very promising strategy for developing red-shifted molecular emitters with an absorption wavelength of ∼600 nm, having no significant impact on the character of the bright S-S1 transition.

2019 ◽  
Author(s):  
Jeffrey Chang ◽  
Matthew Romei ◽  
Steven Boxer

<p>Double-bond photoisomerization in molecules such as the green fluorescent protein (GFP) chromophore can occur either via a volume-demanding one-bond-flip pathway or via a volume-conserving hula-twist pathway. Understanding the factors that determine the pathway of photoisomerization would inform the rational design of photoswitchable GFPs as improved tools for super-resolution microscopy. In this communication, we reveal the photoisomerization pathway of a photoswitchable GFP, rsEGFP2, by solving crystal structures of <i>cis</i> and <i>trans</i> rsEGFP2 containing a monochlorinated chromophore. The position of the chlorine substituent in the <i>trans</i> state breaks the symmetry of the phenolate ring of the chromophore and allows us to distinguish the two pathways. Surprisingly, we find that the pathway depends on the arrangement of protein monomers within the crystal lattice: in a looser packing, the one-bond-flip occurs, whereas in a tighter packing (7% smaller unit cell size), the hula-twist occurs.</p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p> <p> </p>


2017 ◽  
Vol 8 (40) ◽  
pp. 6283-6288 ◽  
Author(s):  
Lei Xu ◽  
Ning Ren ◽  
Ji Pang ◽  
Hongping Deng ◽  
Xinyuan Zhu ◽  
...  

CO2 responsive fluorescent vesicles from a GFP chromophore labeled block-copolymer could change their size and fluorescence to mimic jellyfish breathing.


2018 ◽  
Vol 19 (12) ◽  
pp. 3778 ◽  
Author(s):  
Nina Bozhanova ◽  
Mikhail Baranov ◽  
Nadezhda Baleeva ◽  
Alexey Gavrikov ◽  
Alexander Mishin

Fluorogens are an attractive type of dye for imaging applications, eliminating time-consuming washout steps from staining protocols. With just a handful of reported fluorogen-protein pairs, mostly in the green region of spectra, there is a need for the expansion of their spectral range. Still, the origins of solvatochromic and fluorogenic properties of the chromophores suitable for live-cell imaging are poorly understood. Here we report on the synthesis and labeling applications of novel red-shifted fluorogenic cell-permeable green fluorescent protein (GFP) chromophore analogs.


2002 ◽  
Vol 184 (7) ◽  
pp. 1998-2004 ◽  
Author(s):  
Takako Murakami ◽  
Koki Haga ◽  
Michio Takeuchi ◽  
Tsutomu Sato

ABSTRACT The Bacillus subtilis spoIIIJ gene, which has been proven to be vegetatively expressed, has also been implicated as a sporulation gene. Recent genome sequencing information in many organisms reveals that spoIIIJ and its paralogous gene, yqjG, are conserved from prokaryotes to humans. A homologue of SpoIIIJ/YqjG, the Escherichia coli YidC is involved in the insertion of membrane proteins into the lipid bilayer. On the basis of this similarity, it was proposed that the two homologues act as translocase for the membrane proteins. We studied the requirements for spoIIIJ and yqjG during vegetative growth and sporulation. In rich media, the growth of spoIIIJ and yqjG single mutants were the same as that of the wild type, whereas spoIIIJ yqjG double inactivation was lethal, indicating that together these B. subtilis translocase homologues play an important role in maintaining the viability of the cell. This result also suggests that SpoIIIJ and YqjG probably control significantly overlapping functions during vegetative growth. spoIIIJ mutations have already been established to block sporulation at stage III. In contrast, disruption of yqjG did not interfere with sporulation. We further show that high level expression of spoIIIJ during vegetative phase is dispensable for spore formation, but the sporulation-specific expression of spoIIIJ is necessary for efficient sporulation even at the basal level. Using green fluorescent protein reporter to monitor SpoIIIJ and YqjG localization, we found that the proteins localize at the cell membrane in vegetative cells and at the polar and engulfment septa in sporulating cells. This localization of SpoIIIJ at the sporulation-specific septa may be important for the role of spoIIIJ during sporulation.


1998 ◽  
Vol 39 (29) ◽  
pp. 5239-5242 ◽  
Author(s):  
Satoshi Kojima ◽  
Hiroko Ohkawa ◽  
Takashi Hirano ◽  
Shojiro Maki ◽  
Haruki Niwa ◽  
...  

2001 ◽  
Vol 115 (6) ◽  
pp. 455-464 ◽  
Author(s):  
Xulun Zhang ◽  
Stephan L. Baader ◽  
Feng Bian ◽  
Wolfgang Müller ◽  
John Oberdick

2020 ◽  
Vol 71 (16) ◽  
pp. 4877-4889
Author(s):  
Jie-Yang Lu ◽  
Shuang-Xi Xiong ◽  
Wenzhe Yin ◽  
Xiao-Dong Teng ◽  
Yue Lou ◽  
...  

Abstract Sporophytic pollen coat proteins (sPCPs) derived from the anther tapetum are deposited into pollen wall cavities and function in pollen–stigma interactions, pollen hydration, and environmental protection. In Arabidopsis, 13 highly abundant proteins have been identified in pollen coat, including seven major glycine-rich proteins GRP14, 16, 17, 18, 19, 20, and GRP–oleosin; two caleosin-related family proteins (AT1G23240 and AT1G23250); three lipase proteins EXL4, EXL5 and EXL6, and ATA27/BGLU20. Here, we show that GRP14, 17, 18, 19, and EXL4 and EXL6 fused with green fluorescent protein (GFP) are translated in the tapetum and then accumulate in the anther locule following tapetum degeneration. The expression of these sPCPs is dependent on two essential tapetum transcription factors, MALE STERILE188 (MS188) and MALE STERILITY 1 (MS1). The majority of sPCP genes are up-regulated within 30 h after MS1 induction and could be restored by MS1 expression driven by the MS188 promoter in ms188, indicating that MS1 is sufficient to activate their expression; however, additional MS1 downstream factors appear to be required for high-level sPCP expression. Our ChIP, in vivo transactivation assay, and EMSA data indicate that MS188 directly activates MS1. Together, these results reveal a regulatory cascade whereby outer pollen wall formation is regulated by MS188 followed by synthesis of sPCPs controlled by MS1.


Author(s):  
Kristen A. Zimmermann ◽  
Jianfei Zhang ◽  
Harry Dorn ◽  
Christopher Rylander ◽  
Marissa Nichole Rylander

Carbon nanotubes (CNTs) are attractive materials for early detection, treatment, and imaging of cancer malignancies; however, they are limited by their inability to be monitored in vitro and in vivo [1]. Unlabeled CNTs are difficult to distinguish using elemental analysis because they are composed entirely of carbon, which is also characteristic of cellular membranes. Although some single walled nanotubes (SWNT) have been found to exhibit fluorescent properties, not all particles in a single batch fluoresce [2]. Additionally, these emissions may be too weak to be detected using conventional imaging modalities [3]. Incorporating fluorescent markers, such as fluorescent proteins or quantum dots, allows the non-fluorescent particles to be visualized. Previously, fluorophores, such as green fluorescent protein (GFP) or red fluorescent protein (RFP), have been used to visualize and track cells or other particles in biological environments, but their low quantum yield and tendency to photobleach generate limitations for their use in such applications.


2006 ◽  
Vol 72 (9) ◽  
pp. 6088-6093 ◽  
Author(s):  
Helen Rawsthorne ◽  
Kevin N. Turner ◽  
David A. Mills

ABSTRACT Group II introns are mobile genetic elements that can be redirected to invade specific genes. Here we describe the use of the lactococcal group II intron, Ll.ltrB, to achieve multicopy delivery of heterologous genes into the genome of Lactococcus lactis IL1403-UCD without the need for selectable markers. Ll.ltrB was retargeted to invade three transposase genes, the tra gene found in IS904 (tra904), tra981, and tra983, of which 9, 10, and 14 copies, respectively, were present in IL1403-UCD. Intron invasion of tra904, tra981, and tra983 allele groups occurred at high frequencies, and individual segregants possessed anywhere from one to nine copies of intron in the respective tra alleles. To achieve multicopy delivery of a heterologous gene, a green fluorescent protein (GFP) marker was cloned into the tra904-targeted Ll.ltrB, and the resultant intron (Ll.ltrB::GFP) was induced to invade the L. lactis tra904 alleles. Segregants possessing Ll.ltrB::GFP in three, four, five, six, seven, and eight copies in different tra904 alleles were obtained. In general, increasing the chromosomal copy number of Ll.ltrB::GFP resulted in strains expressing successively higher levels of GFP. However, strains possessing the same number of Ll.ltrB::GFP copies within different sets of tra904 alleles exhibited differential GFP expression, and segregants possessing seven or eight copies of Ll.ltrB::GFP grew poorly upon induction, suggesting that GFP expression from certain combinations of alleles was detrimental. The highest level of GFP expression was observed from a specific six-copy variant that produced GFP at a level analogous to that obtained with a multicopy plasmid. In addition, the high level of GFP expression was stable for over 120 generations. This work demonstrates that stable multicopy integration of heterologous genes can be readily achieved in bacterial genomes with group II intron delivery by targeting repeated elements.


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