Evidence for the Amphipathic Nature and Tilted Topology of Helices 4 and 5 in the Closed State of the Colicin E1 Channel†

Biochemistry ◽  
2009 ◽  
Vol 48 (6) ◽  
pp. 1369-1380 ◽  
Author(s):  
Derek Ho ◽  
A. Rod Merrill
Keyword(s):  
Closed State ◽  
Colicin E1

scholarly journals Solid-state NMR studies of the membrane-bound closed state of the colicin E1 channel domain in lipid bilayers

1998 ◽  
Vol 7 (2) ◽  
pp. 342-348 ◽  
Author(s):  
Yongae Kim ◽  
Kathleen Valentine ◽  
Stanley J. Opella ◽  
Sharon L. Schendel ◽  
William A. Cramer
Keyword(s):  
Solid State ◽  
Lipid Bilayers ◽  
Solid State Nmr ◽  
Nmr Studies ◽  
Closed State ◽  
Colicin E1 ◽  
Membrane Bound

scholarly journals Structure and assembly of double-headed Sendai virus nucleocapsids

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Na Zhang ◽  
Hong Shan ◽  
Mingdong Liu ◽  
Tianhao Li ◽  
Rui Luo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Measles Virus ◽  
Sendai Virus ◽  
Nipah Virus ◽  
Mumps Virus ◽  
Genome Replication ◽  
Direct Visualization ◽  
Closed State ◽  
Cryo Electron Microscopy ◽  
Negative Sense

AbstractParamyxoviruses, including the mumps virus, measles virus, Nipah virus and Sendai virus (SeV), have non-segmented single-stranded negative-sense RNA genomes which are encapsidated by nucleoproteins into helical nucleocapsids. Here, we reported a double-headed SeV nucleocapsid assembled in a tail-to-tail manner, and resolved its helical stems and clam-shaped joint at the respective resolutions of 2.9 and 3.9 Å, via cryo-electron microscopy. Our structures offer important insights into the mechanism of the helical polymerization, in particular via an unnoticed exchange of a N-terminal hole formed by three loops of nucleoproteins, and unveil the clam-shaped joint in a hyper-closed state for nucleocapsid dimerization. Direct visualization of the loop from the disordered C-terminal tail provides structural evidence that C-terminal tail is correlated to the curvature of nucleocapsid and links nucleocapsid condensation and genome replication and transcription with different assembly forms.

Large-scale production of citrate synthase from a cloned gene

1982 ◽  
Vol 60 (12) ◽  
pp. 1143-1147 ◽  
Author(s):  
Harry W. Duckworth ◽  
Alexander W. Bell
Keyword(s):  
Escherichia Coli ◽  
Large Scale ◽  
Citrate Synthase ◽  
Specific Activity ◽  
Tetracycline Resistance ◽  
Scale Production ◽  
Ampicillin Resistance ◽  
Colicin E1 ◽  
Large Scale Production ◽  
Cloned Gene

Starting with a colicin E1 resistance recombinant plasmid which contains gltA, the gene for citrate synthase in Escherichia coli, we have constructed an ampicillin-resistance plasmid containing the gltA region as a 2.9-kilobase-pair insert in the tetracycline-resistance region of pBR322. Escherichia coli HB101 harbouring this plasmid, when grown on rich medium containing ampicillin, contains citrate synthase as about 8% of its soluble protein. The enzyme has been purified from this rich source and is identical to the chromosomal enzyme prepared previously in every property tested, except for specific activity, which is 64 U∙mg−1 as compared with 45–50 U∙mg−1 previously obtained. The N-terminal sequences of both enzymes are reported, and they are identical up to residue 16 at least. The overall yield of pure enzyme, starting with the cells grown in 15 L of medium, is 600–800 mg.

scholarly journals State-Dependent Crosslinking in IKS Demonstrates a Closed-State Interaction between KCNE1 at F57 and KCNQ1 that Inhibits Channel Opening

2014 ◽  
Vol 106 (2) ◽  
pp. 16a
Author(s):  
Christopher I. Murray ◽  
Yasmeen Maurice ◽  
Jodene Eldstrom ◽  
David Fedida
Keyword(s):  
State Interaction ◽  
Closed State ◽  
State Dependent ◽  
Channel Opening

scholarly journals Effects of Strontium on the Permeation and Gating Phenotype of Calcium Channels in Hair Cells

2008 ◽  
Vol 100 (4) ◽  
pp. 2115-2124 ◽  
Author(s):  
Adrian Rodriguez-Contreras ◽  
Ping Lv ◽  
Jun Zhu ◽  
Hyo Jeong Kim ◽  
Ebenezer N. Yamoah
Keyword(s):  
Hair Cell ◽  
Single Channel ◽  
Single Channels ◽  
Physiological Concentration ◽  
Closed State ◽  
Dependent Inactivation ◽  
Intracellular Ca ◽  
High Concentrations ◽  
Latency Distributions ◽  
Channel Properties

To minimize the effects of Ca2+ buffering and signaling, this study sought to examine single Ca2+ channel properties using Sr2+ ions, which substitute well for Ca2+ but bind weakly to intracellular Ca2+ buffers. Two single-channel fluctuations were distinguished by their sensitivity to dihydropyridine agonist (L-type) and insensitivity toward dihydropyridine antagonist (non-L-type). The L- and non-L-type single channels were observed with single-channel conductances of 16 and 19 pS at 70 mM Sr2+ and 11 and 13 pS at 5 mM Sr2+, respectively. We obtained KD estimates of 5.2 and 1.9 mM for Sr2+ for L- and non-L-type channels, respectively. At Ca2+ concentration of ∼2 mM, the single-channel conductances of Sr2+ for the L-type channel was ∼1.5 and 4.0 pS for the non-L-type channels. Thus the limits of single-channel microdomain at the membrane potential of a hair cell (e.g., −65 mV) for Sr2+ ranges from 800 to 2,000 ion/ms, assuming an ECa of 100 mV. The channels are ≥4-fold more sensitive at the physiological concentration ranges than at concentrations >10 mM. Additionally, the channels have the propensity to dwell in the closed state at high concentrations of Sr2+, which is reflected in the time constant of the first latency distributions. It is concluded that the concentration of the permeant ion modulates the gating of hair cell Ca2+ channels. Finally, the closed state/s that is/are altered by high concentrations of Sr2+ may represent divalent ion-dependent inactivation of the L-type channel.

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