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2021 ◽  
Vol 118 (30) ◽  
pp. e2105447118
Author(s):  
Maria A. Schumacher ◽  
Kelley A. Gallagher ◽  
Neil A. Holmes ◽  
Govind Chandra ◽  
Max Henderson ◽  
...  

Filamentous actinobacteria of the genus Streptomyces have a complex lifecycle involving the differentiation of reproductive aerial hyphae into spores. We recently showed c-di-GMP controls this transition by arming a unique anti-σ, RsiG, to bind the sporulation-specific σ, WhiG. The Streptomyces venezuelae RsiG–(c-di-GMP)2–WhiG structure revealed that a monomeric RsiG binds c-di-GMP via two E(X)3S(X)2R(X)3Q(X)3D repeat motifs, one on each helix of an antiparallel coiled-coil. Here we show that RsiG homologs are found scattered throughout the Actinobacteria. Strikingly, RsiGs from unicellular bacteria descending from the most basal branch of the Actinobacteria are small proteins containing only one c-di-GMP binding motif, yet still bind their WhiG partners. Our structure of a Rubrobacter radiotolerans (RsiG)2–(c-di-GMP)2–WhiG complex revealed that these single-motif RsiGs are able to form an antiparallel coiled-coil through homodimerization, thereby allowing them to bind c-di-GMP similar to the monomeric twin-motif RsiGs. Further data show that in the unicellular actinobacterium R. radiotolerans, the (RsiG)2–(c-di-GMP)2–WhiG regulatory switch controls type IV pilus expression. Phylogenetic analysis indicates the single-motif RsiGs likely represent the ancestral state and an internal gene-duplication event gave rise to the twin-motif RsiGs inherited elsewhere in the Actinobacteria. Thus, these studies show how the anti-σ RsiG has evolved through an intragenic duplication event from a small protein carrying a single c-di-GMP binding motif, which functions as a homodimer, to a larger protein carrying two c-di-GMP binding motifs, which functions as a monomer. Consistent with this, our structures reveal potential selective advantages of the monomeric twin-motif anti-σ factors.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Negar Afshar ◽  
Bilge Argunhan ◽  
Maierdan Palihati ◽  
Goki Taniguchi ◽  
Hideo Tsubouchi ◽  
...  

Homologous recombination (HR) is essential for maintaining genome stability. Although Rad51 is the key protein that drives HR, multiple auxiliary factors interact with Rad51 to potentiate its activity. Here, we present an interdisciplinary characterization of the interactions between Rad51 and these factors. Through structural analysis, we identified an evolutionarily conserved acidic patch of Rad51. The neutralization of this patch completely abolished recombinational DNA repair due to defects in the recruitment of Rad51 to DNA damage sites. This acidic patch was found to be important for the interaction with Rad55-Rad57 and essential for the interaction with Rad52. Furthermore, biochemical reconstitutions demonstrated that neutralization of this acidic patch also impaired the interaction with Rad54, indicating that a single motif is important for the interaction with multiple auxiliary factors. We propose that this patch is a fundamental motif that facilitates interactions with auxiliary factors and is therefore essential for recombinational DNA repair.


Our Nature ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 16-27
Author(s):  
J. Karna ◽  
B. R. Subba ◽  
H. Bhattacharya ◽  
D. T. Chhetry

Oriental Magpie Robin is a song bird that resides in some tropical regions of Asia. The present work was attempted to provide a detailed study of the territorial singing of this species in the area of Biratnagar (Nepal). Songs of Oriental Magpie Robin was recorded by using a digital voice recorder (Olympus VN-8700PC) for one hour without break at seven selected sites in Biratnagar. Recorded songs were converted in the form of spectrogram by using avisoft. Seven Oriental Magpie Robins, belonging to seven different study sites of Biratnagar were taken as subjects and have been abbreviated as Bird A, B, C, D, E, F and G respectively. It was very surprising that there was not even a single motif which was matching among any of the birds. Out of 1782 song samples recorded from seven individuals, 328 types of songs were identified. These songs were composed of 3 to 18 types of elements.


2020 ◽  
pp. 151-185
Author(s):  
Bart Huelsenbeck

This chapter traces a single motif—that of the ‘Ocean’—within Seneca’s Suasoriae. This theme spans the declamations of Argentarius, Pompeius Silo, Moschus, Musa, Albucius Silus, and Papirius Fabianus, as well as verses by Albinovanus Pedo and excerpts from the History of Alexander by Quintus Curtius Rufus. By comparing how these declaimers and authors introduce variations around the idea of an ‘ocean’ while maintaining its overall characteristics (e.g. darkness, monstrousness, sluggishness), this chapter identifies two overarching concepts which governed declamatory improvisation. On the one hand, ‘scalability’ allowed declaimers to compose speeches of different lengths while maintaining thematic coherence through the use of similar core-structures; on the other, the principle of ‘sequence’ dictated that each declaimer spoke in response to another. These parallel concepts enabled declamatory themes to gain new meanings through an ongoing accumulation of arguments and contributed to declamation’s status as a dynamic, interactive process.


Author(s):  
Valentina E. Vetlovskaya ◽  

The article considers literary self-definition of Fyodor Dostoevsky at the starting point of his career as a writer. Its purpose is to reveal connections of the young author with contemporary writers and his place in the literary process on the basis of specific texts. The article continues the research presented in two articles published in 2013 and examines a wider range of texts related to Dostoevsky’s first novel, Poor Folk. By applying the principles of comparative analysis to the repeated narrative elements, the author of the article shows that Mikhail Voskresensky’s story “Zamoskvoretskie Tereza i Faldoni” (1843), which is considered to be parodied in Poor Folk, has just one common feature with Dostoevsky's novel: names of one main and one secondary character. The names refer to a popular sentimental novel by Nicolas Germain Léonard (1783), retold with disapproval by N. M. Karamzin, while Voskresensky’s story was unworthy even of caricature for the insignificance of its content and its poetics. It should also be noted that not a single motif that exclusively belongs to this story was reproduced by Dostoevsky at any time later. The situation is quite different in the case of Alexandre Dumas’s novel The Conspirators (Le Chevalier d’Harmental), published in a newspaper in 1841–1842 and as a separate edition in 1843. The novel’s plot twists, main characters, some features of their personalities and some details regarding what happens to them are reflected in Poor Folk. But this was not done for reasons of parody. Dostoevsky chose the novel by the famous Frenchman only to promote his own world view and the new principles of art – the nascent realism with its unadorned “truth of life”, harsh and often tragic reality in contrast to the benevolent romanticism


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Morgane Rosendale ◽  
Thi Nhu Ngoc Van ◽  
Dolors Grillo-Bosch ◽  
Silvia Sposini ◽  
Léa Claverie ◽  
...  

Abstract During clathrin mediated endocytosis (CME), the concerted action of dynamin and its interacting partners drives membrane scission. Essential interactions occur between the proline/arginine-rich domain of dynamin (dynPRD) and the Src-homology domain 3 (SH3) of various proteins including amphiphysins. Here we show that multiple SH3 domains must bind simultaneously to dynPRD through three adjacent motifs for dynamin’s efficient recruitment and function. First, we show that mutant dynamins modified in a single motif, including the central amphiphysin SH3 (amphSH3) binding motif, partially rescue CME in dynamin triple knock-out cells. However, mutating two motifs largely prevents that ability. Furthermore, we designed divalent dynPRD-derived peptides. These ligands bind multimers of amphSH3 with >100-fold higher affinity than monovalent ones in vitro. Accordingly, dialyzing living cells with these divalent peptides through a patch-clamp pipette blocks CME much more effectively than with monovalent ones. We conclude that dynamin drives vesicle scission via multivalent interactions in cells.


2018 ◽  
Author(s):  
Morgane Rosendale ◽  
Thi Nhu Ngoc Van ◽  
Dolors Grillo-Bosch ◽  
Silvia Sposini ◽  
Léa Claverie ◽  
...  

AbstractDuring clathrin mediated endocytosis (CME), membrane scission is achieved by the concerted action of dynamin and its interacting partners. Essential interactions occur between the proline/arginine-rich domain of dynamin (dynPRD) and the Src-homology domain 3 (SH3) of various proteins including amphiphysins. Here we show that multiple SH3 domains must bind simultaneously to dynPRD through three adjacent motifs for dynamin’s efficient recruitment and function. First, we show in dynamin triple knock-out cells that mutant dynamins modified in a single motif, including the central amphiphysin SH3 (amphSH3) binding motif, are partially capable of rescuing CME. However, mutating two motifs largely prevents that ability. To support this observation, we designed divalent dynPRD-derived peptides. These ligands bind multimers of amphSH3 with >100-fold higher affinity than monovalent onesin vitro. Accordingly, dialyzing living cells with these divalent peptides through a patch-clamp pipette blocks CME 2 to 3 times more effectively than with monovalent ones. Finally, the frequency of endocytic events decreases with competing peptides or hypomorphic rescue mutants but the kinetics of dynamin recruitment is unaffected. This suggests that PRD-SH3 interactions act upstream of dynamin accumulation at the neck of nascent vesicles. We conclude from these data that dynamin drives vesicle scissionviamultivalent interactionsin vivo.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Madhu S. Pandey ◽  
Edward N. Harris ◽  
Paul H. Weigel

The hyaluronan (HA) receptor for endocytosis (HARE) is a multifunctional recycling clearance receptor for 14 different ligands, including HA and heparin (Hep), which bind to discrete nonoverlapping sites. Four different functional endocytic motifs (M) in the cytoplasmic domain (CD) target coated pit mediated uptake: (YSYFRI2485(M1), FQHF2495(M2), NPLY2519(M3), and DPF2534(M4)). We previously found (Pandey et al. J. Biol. Chem. 283, 21453, 2008) thatM1,M2, andM3mediate endocytosis of HA. Here we assessed the ability of HARE variants with a single-motif deletion or containing only a single motif to endocytose HA or Hep. Single-motif deletion variants lackingM1, M3, orM4(a different subset than involved in HA uptake) showed decreased Hep endocytosis, althoughM3was the most active; the remaining redundant motifs did not compensate for loss of other motifs. Surprisingly, a HARE CD variant with onlyM3internalized both HA and Hep, whereas variants with eitherM2orM4alone did not endocytose either ligand. Internalization of HA and Hep by HARE CD mutants was dynamin-dependent and was inhibited by hyperosmolarity, confirming clathrin-mediated endocytosis. The results indicate a complicated relationship among multiple CD motifs that target coated pit uptake and a more fundamental role for motifM3.


FEBS Letters ◽  
2012 ◽  
Vol 586 (19) ◽  
pp. 3398-3403 ◽  
Author(s):  
Joel Osuna ◽  
Humberto Flores ◽  
Paul Gaytán
Keyword(s):  

2006 ◽  
Vol 15 (2) ◽  
pp. 141-158 ◽  
Author(s):  
Ida Klitgård

This article addresses the ways in which the Danish translator Mogens Boisen manages to translate the shapeshifting nature of the style and content of the ‘Proteus’ episode of James Joyce’s Ulysses (1922) in his three published translations of the novel in 1949, 1970 and 1980. The discussion includes an analysis of the translation of the lyrical blend of seascape and myth, language transformations, pseudo-Homeric compounds, grammatical transfers and the symbolism of a single motif with important bearings on the complex theme of protean change. I argue that the early translation seeks to domesticate and make fluent what is complicated, whereas the later translations have become more sensitive towards stylistic transformation and defamiliarization.


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