scholarly journals Membrane binding of zebrafish actinoporin-like protein: AF domains, a novel superfamily of cell membrane binding domains

2006 ◽  
Vol 398 (3) ◽  
pp. 381-392 ◽  
Author(s):  
Ion Gutiérrez-Aguirre ◽  
Peter Trontelj ◽  
Peter Maček ◽  
Jeremy H. Lakey ◽  
Gregor Anderluh

Actinoporins are potent eukaryotic pore-forming toxins specific for sphingomyelin-containing membranes. They are structurally similar to members of the fungal fruit-body lectin family that bind cell-surface exposed Thomsen–Friedenreich antigen. In the present study we found a number of sequences in public databases with similarity to actinoporins. They originate from three animal and two plant phyla and can be classified in three families according to phylogenetic analysis. The sequence similarity is confined to a region from the C-terminal half of the actinoporin molecule and comprises the membrane binding site with a highly conserved P-[WYF]-D pattern. A member of this novel actinoporin-like protein family from zebrafish was cloned and expressed in Escherichia coli. It displays membrane-binding behaviour but does not have permeabilizing activity or sphingomyelin specificity, two properties typical of actinoporins. We propose that the three families of actinoporin-like proteins and the fungal fruit-body lectin family comprise a novel superfamily of membrane binding proteins, tentatively called AF domains (abbreviated from actinoporin-like proteins and fungal fruit-body lectins).

2001 ◽  
Vol 45 (10) ◽  
pp. 2813-2819 ◽  
Author(s):  
M. Clelia Ganoza ◽  
Michael C. Kiel

ABSTRACT We demonstrate that the transfer of fully charged aminoacyl-tRNAs into peptides directed by the MS2 RNA template requires both ATP and GTP, initiation factors (IF1, IF2, and IF3), elongation factors (EF-Tu, EF-Ts, and EF-G), and the ribosomal ATPase (RbbA). The nonhydrolyzable analogue AMPPCP inhibits the reactions, suggesting that hydrolysis of ATP is required for synthesis. The RbbA protein occurs bound to ribosomes and stimulates the ATPase activity of Escherichia coli 70S and 30S particles. The gene encoding RbbA harbors four ATP binding domains; the C-terminal half of the protein bears extensive sequence similarity to EF-3, a ribosome-dependent ATPase. Here, we show that the antibiotic hygromycin B selectively inhibits the ATPase activity of RbbA. Other antibiotics with similar effects on miscoding, streptomycin and neomycin, as well as antibiotics that impair peptide bond synthesis and translocation, had little effect on the ATPase activity of RbbA on 70S ribosomes. Immunoblot analysis indicates that at physiological concentrations, hygromycin B selectively releases RbbA from 70S ribosomes. Hygromycin B protects G1494 and A1408 in the decoding region, and RbbA enhances the reactivity of A889 and G890 of the 16S rRNA switch helix region. Cross-linking and X-ray diffraction data have revealed that this helix switch and the decoding region are in close proximity. Mutations in the switch helix (889-890) region affect translational fidelity and translocation. The binding site of hygromycin B and its known dual effect on the fidelity of decoding and translocation suggest a model for the action of this drug on ribosomes.


2019 ◽  
Vol 202 (6) ◽  
Author(s):  
Kara M. Schoenemann ◽  
Daniel E. Vega ◽  
William Margolin

ABSTRACT Bacteria such as Escherichia coli divide by organizing filaments of FtsZ, a tubulin homolog that assembles into dynamic treadmilling membrane-associated protein filaments at the cell midpoint. FtsA and ZipA proteins are required to tether these filaments to the inner face of the cytoplasmic membrane, and loss of either tether is lethal. ZipA from E. coli and other closely related species harbors a long linker region that connects the essential N-terminal transmembrane domain to the C-terminal globular FtsZ-binding domain, and part of this linker includes a P/Q-rich peptide that is predicted to be intrinsically disordered. We found unexpectedly that several large deletions of the ZipA linker region, including the entire P/Q rich peptide, had no effect on cell division under normal conditions. However, we found that the loss of the P/Q region made cells more resistant to excess levels of FtsA and more sensitive to conditions that displaced FtsA from FtsZ. FtsA also harbors a short ∼20-residue peptide linker that connects the main globular domain with the C-terminal amphipathic helix that is important for membrane binding. In analogy with ZipA, deletion of 11 of the central residues in the FtsA linker had little effect on FtsA function in cell division. IMPORTANCE Escherichia coli cells divide using a cytokinetic ring composed of polymers of the tubulin-like FtsZ. To function properly, these polymers must attach to the inner surface of the cytoplasmic membrane via two essential membrane-associated tethers, FtsA and ZipA. Both FtsA and ZipA contain peptide linkers that connect their membrane-binding domains with their FtsZ-binding domains. Although they are presumed to be crucial for cell division activity, the importance of these linkers has not yet been rigorously tested. Here, we show that large segments of these linkers can be removed with few consequences for cell division, although several subtle defects were uncovered. Our results suggest that ZipA, in particular, can function in cell division without an extended linker.


2016 ◽  
Vol 25 (17) ◽  
pp. 3647-3653 ◽  
Author(s):  
Junling Zhao ◽  
Kasun Kodippili ◽  
Yongping Yue ◽  
Chady H. Hakim ◽  
Lakmini Wasala ◽  
...  

Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 15
Author(s):  
Badreddine Sijilmassi ◽  
Abdelkarim Filali-Maltouf ◽  
Hassan Boulahyaoui ◽  
Aymane Kricha ◽  
Kenza Boubekri ◽  
...  

A total of 14 Rhizobium strains were isolated from lentil accessions grown at the ICARDA experimental research station at Marchouch in Morocco and used for molecular characterization and symbiotic efficiency assessment. Individual phylogenetic analysis using the 16S rRNA gene, house-keeping genes rpoB, recA, and gyrB, and symbiotic genes nodD and nodA along with Multilocus Sequence Analysis (MLSA) of the concatenated genes (16S rRNA-rpoB-recA-gyrB) was carried out for the identification and clustering of the isolates. The symbiotic efficiency of the strains was assessed on three Moroccan lentil cultivars (Bakria, Chakkouf, and Zaria) based on the number of nodules, plant height, plant dry weight, and total nitrogen content in leaves. The results showed that the individual phylogenetic analysis clustered all the strains into Rhizobium laguerreae and Rhizobium leguminosarum with sequence similarity ranging from 94 to 100%, except one strain which clustered with Mesorhizobium huakuii with sequence similarity of 100%. The MLSA of the concatenated genes and the related percentages of similarity clustered these strains into two groups of Rhizobium species, with one strain as a new genospecies when applying the threshold of 96%. For symbiotic efficiency, the Bakria variety showed the best association with 10 strains compared to its non-inoculated control (p-value ≤ 0.05), followed by Chakkouf and Zaria. The present study concluded that the genetic diversity and the symbiotic efficiency of Rhizobium strains appeared to be mainly under the control of the lentil genotypes.


Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1692
Author(s):  
Li Gu ◽  
Ting Su ◽  
Ming-Tai An ◽  
Guo-Xiong Hu

Oreocharis esquirolii, a member of Gesneriaceae, is known as Thamnocharis esquirolii, which has been regarded a synonym of the former. The species is endemic to Guizhou, southwestern China, and is evaluated as vulnerable (VU) under the International Union for Conservation of Nature (IUCN) criteria. Until now, the sequence and genome information of O. esquirolii remains unknown. In this study, we assembled and characterized the complete chloroplast (cp) genome of O. esquirolii using Illumina sequencing data for the first time. The total length of the cp genome was 154,069 bp with a typical quadripartite structure consisting of a pair of inverted repeats (IRs) of 25,392 bp separated by a large single copy region (LSC) of 85,156 bp and a small single copy region (SSC) of18,129 bp. The genome comprised 114 unique genes with 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. Thirty-one repeat sequences and 74 simple sequence repeats (SSRs) were identified. Genome alignment across five plastid genomes of Gesneriaceae indicated a high sequence similarity. Four highly variable sites (rps16-trnQ, trnS-trnG, ndhF-rpl32, and ycf 1) were identified. Phylogenetic analysis indicated that O. esquirolii grouped together with O. mileensis, supporting resurrection of the name Oreocharis esquirolii from Thamnocharisesquirolii. The complete cp genome sequence will contribute to further studies in molecular identification, genetic diversity, and phylogeny.


2011 ◽  
Vol 61 (12) ◽  
pp. 2974-2978 ◽  
Author(s):  
Jinxing Zhu ◽  
Xiaoli Liu ◽  
Xiuzhu Dong

Two mesophilic methanogenic strains, designated TS-2T and GHT, were isolated from sediments of Tuosu lake and Gahai lake, respectively, in the Qaidam basin, Qinghai province, China. Cells of both isolates were rods (about 0.3–0.5×2–5 µm) with blunt rounded ends and Gram-staining-positive. Strain TS-2T was motile with one or two polar flagella and used only H2/CO2 for growth and methanogenesis. Strain GHT was non-motile, used both H2/CO2 and formate and displayed a variable cell arrangement depending on the substrate: long chains when growing in formate (50 mM) or under high pressure H2 and single cells under low pressure H2. Phylogenetic analysis based on 16S rRNA gene sequences placed the two isolates in the genus Methanobacterium. Strain TS-2T was most closely related to Methanobacterium alcaliphilum NBRC 105226T (96 % 16S rRNA gene sequence similarity). Phylogenetic analysis based on the alpha subunit of methyl-coenzyme M reductase also supported the affiliation of the two isolates with the genus Methanobacterium. DNA–DNA relatedness between the isolates and M. alcaliphilum DSM 3387T was 39–53 %. Hence we propose two novel species, Methanobacterium movens sp. nov. (type strain TS-2T = AS 1.5093T = JCM 15415T) and Methanobacterium flexile sp. nov. (type strain GHT = AS 1.5092T = JCM 15416T).


2021 ◽  
Author(s):  
Saowapha Surawut ◽  
Sorasak Nak-aim ◽  
Chutapa Kunsook ◽  
Laddawan Kamhaengkul ◽  
Pornpimon Kanjanavas ◽  
...  

Abstract Ascomycetes mushrooms are fungi that produce ascospores in asci and some with perithecia. Not only they have a role of decomposer in ecology but also produced some bioactive compound, anti-microbial activity, and cytotoxicity. This study aims to explore the diversity of ascomycetes mushroom species in para rubber plantations and to identify them by morphological and sequence analysis of the internal transcribed spacer (ITS) region. The results found ascomycetes mushroom consist of Trichoderma pezizoides (RP1, % identity 98.79, DQ835513.1), Daldinia eschscholtzii (RP2, % identity 100, MN310384.1), Cookeina sulcipes (RP3, % identity 98.44, KY094620.1), Cookeina garethjonesii (RP4, % identity 99.06, KY094622.1), Cookeina tricholoma (RP5, % identity 100, KY094619.1) and Xylaria terricola (RP6, % identity 88.42, MF577038.1). Most of the ascomycetes in this study have previously been described in Thailand except Xylaria terricola. Additionally, phylogenetic analysis of ascomycetes mushroom showed high genetic relatedness with reference strains. Therefore, the sequence similarity and phylogenetic analysis confirmed the identity of six ascomycetes mushroom species, and further study of bioactive compound from these mushrooms may be investigated for other applications.


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