Voltage-gated proton channels from fungi highlight role of peripheral regions in channel activation

AbstractHere, we report the identification and characterization of the first proton channels from fungi. The fungal proteins are related to animal voltage-gated Hv channels and are conserved in both higher and lower fungi. Channels from Basidiomycota and Ascomycota appear to be evolutionally and functionally distinct. Representatives from the two phyla share several features with their animal counterparts, including structural organization and strong proton selectivity, but they differ from each other and from animal Hvs in terms of voltage range of activation, pharmacology, and pH sensitivity. The activation gate of Hv channels is believed to be contained within the transmembrane core of the protein and little is known about contributions of peripheral regions to the activation mechanism. Using a chimeragenesis approach, we find that intra- and extracellular peripheral regions are main determinants of the voltage range of activation in fungal channels, highlighting the role of these overlooked components in channel gating.

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85: Identification and characterization of an original mechanism of resistance to gefitinib in non-small lung cancers: role of amphiregulin

Bulletin du Cancer ◽

10.1016/s0007-4551(15)31178-4 ◽

2010 ◽

Vol 97 (1) ◽

pp. S70-S71

Author(s):

Busser Benoît ◽

Lucie Sancey ◽

Véronique Josserand ◽

Saadi Khochbin ◽

Jean-Luc Coll ◽

...

Keyword(s):

Lung Cancers ◽

Mechanism Of Resistance ◽

Identification And Characterization

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Insight into the essential role of the Helicobacter pylori HP1043 orphan response regulator: genome-wide identification and characterization of the DNA-binding sites

Scientific Reports ◽

10.1038/srep41063 ◽

2017 ◽

Vol 7 (1) ◽

Cited By ~ 14

Author(s):

Simone Pelliciari ◽

Eva Pinatel ◽

Andrea Vannini ◽

Clelia Peano ◽

Simone Puccio ◽

...

Keyword(s):

Helicobacter Pylori ◽

Binding Sites ◽

Essential Role ◽

Response Regulator ◽

Dna Binding Sites ◽

Genome Wide ◽

Identification And Characterization ◽

Insight Into

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A small mitochondrial protein present in myzozoans is essential for malaria transmission

Open Biology ◽

10.1098/rsob.160034 ◽

2016 ◽

Vol 6 (4) ◽

pp. 160034 ◽

Cited By ~ 9

Author(s):

Dennis Klug ◽

Gunnar R. Mair ◽

Friedrich Frischknecht ◽

Ross G. Douglas

Keyword(s):

Drug Targets ◽

Mitochondrial Protein ◽

Sister Group ◽

Developmental Defect ◽

Mitochondrial Mass ◽

First Time ◽

Potential Drug Targets ◽

Identification And Characterization

Myzozoans (which include dinoflagellates, chromerids and apicomplexans) display notable divergence from their ciliate sister group, including a reduced mitochondrial genome and divergent metabolic processes. The factors contributing to these divergent processes are still poorly understood and could serve as potential drug targets in disease-causing protists. Here, we report the identification and characterization of a small mitochondrial protein from the rodent-infecting apicomplexan parasite Plasmodium berghei that is essential for development in its mosquito host. Parasites lacking the gene mitochondrial protein ookinete developmental defect ( mpodd ) showed malformed parasites that were unable to transmit to mosquitoes. Knockout parasites displayed reduced mitochondrial mass without affecting organelle integrity, indicating no role of the protein in mitochondrial biogenesis or morphology maintenance but a likely role in mitochondrial import or metabolism. Using genetic complementation experiments, we identified a previously unrecognized Plasmodium falciparum homologue that can rescue the mpodd(−) phenotype, thereby showing that the gene is functionally conserved. As far as can be detected, mpodd is found in myzozoans, has homologues in the phylum Apicomplexa and appears to have arisen in free-living dinoflagellates. This suggests that the MPODD protein has a conserved mitochondrial role that is important for myzozoans. While previous studies identified a number of essential proteins which are generally highly conserved evolutionarily, our study identifies, for the first time, a non-canonical protein fulfilling a crucial function in the mitochondrion during parasite transmission.

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Identification and Characterization of the Penicillin-Binding Protein 2a of Streptococcus pneumoniae and Its Possible Role in Resistance to β-Lactam Antibiotics

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.44.6.1745-1748.2000 ◽

2000 ◽

Vol 44 (6) ◽

pp. 1745-1748 ◽

Cited By ~ 20

Author(s):

Genshi Zhao ◽

Timothy I. Meier ◽

Joann Hoskins ◽

Kelly A. McAllister

Keyword(s):

Streptococcus Pneumoniae ◽

Binding Protein ◽

Penicillin Resistance ◽

Penicillin Binding Protein ◽

Insertional Mutant ◽

Identification And Characterization

ABSTRACT To further understand the role of penicillin-binding protein 2a (PBP 2a) of Streptococcus pneumoniae in penicillin resistance, we confirmed the identity of the protein as PBP 2a. The PBP 2a protein migrated electrophoretically to a position corresponding to that of PBP 2x, PBP 2a, and PBP 2b of S. pneumoniae and was absent in a pbp2ainsertional mutant of S. pneumoniae. We found that the affinities of PBP 2a for penicillins were lower than for cephalosporins and a carbapenem. When compared with other S. pneumoniae PBPs, PBP 2a exhibited lower affinities for β-lactam antibiotics, especially penicillins. Therefore, PBP 2a is a low-affinity PBP for β-lactam antibiotics in S. pneumoniae.

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Identification and characterization of the minimal promoter of Mipu1: the role of GC boxes in the regulation of basal transcription

Acta Biochimica et Biophysica Sinica ◽

10.1093/abbs/gmp019 ◽

2009 ◽

Vol 41 (4) ◽

pp. 309-315 ◽

Cited By ~ 2

Author(s):

B. Lv ◽

Y. Tang ◽

X. Li ◽

G. Wang ◽

C. Yuan ◽

...

Keyword(s):

Minimal Promoter ◽

Basal Transcription ◽

Identification And Characterization

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Identification and Characterization of Two Bordetella avium Gene Products Required for Hemagglutination

Infection and Immunity ◽

10.1128/iai.00140-10 ◽

2010 ◽

Vol 78 (6) ◽

pp. 2370-2376 ◽

Cited By ~ 14

Author(s):

Louise M. Temple ◽

David M. Miyamoto ◽

Manju Mehta ◽

Christian M. Capitini ◽

Stephen Von Stetina ◽

...

Keyword(s):

Whooping Cough ◽

Bioinformatic Analysis ◽

Tracheal Ring ◽

Tracheal Cell ◽

Bordetella Avium ◽

Identification And Characterization

ABSTRACT Bordetella avium causes bordetellosis in birds, a disease similar to whooping cough caused by Bordetella pertussis in children. B. avium agglutinates guinea pig erythrocytes via an unknown mechanism. Loss of hemagglutination ability results in attenuation. We report the use of transposon mutagenesis to identify two genes required for hemagglutination. The genes (hagA and hagB) were adjacent and divergently oriented and had no orthologs in the genomes of other Bordetella species. Construction of in-frame, unmarked mutations in each gene allowed examination of the role of each in conferring erythrocyte agglutination, explanted tracheal cell adherence, and turkey poult tracheal colonization. In all of the in vitro and in vivo assays, the requirement for the trans-acting products of hagA and hagB (HagA and HagB) was readily shown. Western blotting, using antibodies to purified HagA and HagB, revealed proteins of the predicted sizes of HagA and HagB in an outer membrane-enriched fraction. Antiserum to HagB, but not HagA, blocked B. avium erythrocyte agglutination and explanted turkey tracheal ring binding. Bioinformatic analysis indicated the similarity of HagA and HagB to several two-component secretory apparatuses in which one product facilitates the exposition of the other. HagB has the potential to serve as a useful immunogen to protect turkeys against colonization and subsequent disease.

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Identification and Characterization of a Well-Defined Series of Coronatine Biosynthetic Mutants of Pseudomonas syringae pv. tomato DC3000

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2004.17.2.162 ◽

2004 ◽

Vol 17 (2) ◽

pp. 162-174 ◽

Cited By ~ 137

Author(s):

David M. Brooks ◽

Gustavo Hernández-Guzmán ◽

Andrew P. Kloek ◽

Francisco Alarcón-Chaidez ◽

Aswathy Sreedharan ◽

...

Keyword(s):

Pseudomonas Syringae ◽

High Performance ◽

Tomato Dc3000 ◽

Disease Symptoms ◽

Coronafacic Acid ◽

Tn5 Mutants ◽

Cor Genes ◽

Identification And Characterization

To identify Pseudomonas syringae pv. tomato genes involved in pathogenesis, we carried out a screen for Tn5 mutants of P. syringae pv. tomato DC3000 with reduced virulence on Arabidopsis thaliana. Several mutants defining both known and novel virulence loci were identified. Six mutants contained insertions in biosynthetic genes for the phytotoxin coronatine (COR). The P. syringae pv. tomato DC3000 COR genes are chromosomally encoded and are arranged in two separate clusters, which encode enzymes responsible for the synthesis of coronafacic acid (CFA) or coronamic acid (CMA), the two defined intermediates in COR biosynthesis. High-performance liquid chromatography fractionation and exogenous feeding studies confirmed that Tn5 insertions in the cfa and cma genes disrupt CFA and CMA biosynthesis, respectively. All six COR biosynthetic mutants were significantly impaired in their ability to multiply to high levels and to elicit disease symptoms on A. thaliana plants. To assess the relative contributions of CFA, CMA, and COR in virulence, we constructed and characterized cfa6 cmaA double mutant strains. These exhibited virulence phenotypes on A. thalliana identical to those observed for the cmaA or cfa6 single mutants, suggesting that reduced virulence of these mutants on A. thaliana is caused by the absence of the intact COR toxin. This is the first study to use biochemically and genetically defined COR mutants to address the role of COR in pathogenesis.

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Identification and characterization of rapidly dividing U937 clones with differential telomerase activity and gene expression profiles: role of c-Myc/Mad1 and Id/Ets proteins

Leukemia ◽

10.1038/sj.leu.2402607 ◽

2002 ◽

Vol 16 (9) ◽

pp. 1877-1880 ◽

Cited By ~ 15

Author(s):

X Xiao ◽

SK Phogat ◽

IA Sidorov ◽

J Yang ◽

I Horikawa ◽

...

Keyword(s):

Gene Expression ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Telomerase Activity ◽

Ets Proteins ◽

Identification And Characterization

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Identification and characterization of aging products in the glyoxal/ammonium sulfate system - implications for light-absorbing material in atmospheric aerosols

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-6235-2012 ◽

2012 ◽

Vol 12 (2) ◽

pp. 6235-6262

Author(s):

C. J. Kampf ◽

R. Jakob ◽

T. Hoffmann

Keyword(s):

Ammonium Sulfate ◽

Atmospheric Aerosols ◽

Molar Absorptivity ◽

Molecular Product ◽

Product Identification ◽

Absorbing Material ◽

Identification And Characterization ◽

Absorbance Band

Abstract. In this study we report the identification of bicyclic imidazoles in aqueous aerosol mimics using HPLC-ESI-MS/MS. 2,2´-Biimidazole was identified to be a major contributor to the 280 nm absorbance band observed in mixtures of glyoxal and ammonium sulfate, despite the fact that its production rate is two orders of magnitude lower than the previously reported production rates of imidazole or imidazole-2-carboxaldehyde. The molar absorptivity of 2,2´-biimidazole was determined to be (36 690&pm;998) M−1 cm−1. This demonstrates the necessity of molecular product identification at trace levels to enable a better understanding of relevant absorbing species. Additionally the formation of lower polarity products including formamides of imidazoles is proposed. The role of imidazoles and other light-absorbing species in the formation of SOA and optical properties of SOA is discussed and potentially interesting fields for future investigations are outlined.

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