scholarly journals An arginine tetrad as mediator of input-dependent and input-independent ATPases in the clock protein KaiC

2014 ◽  
Vol 70 (5) ◽  
pp. 1375-1390 ◽  
Author(s):  
Rekha Pattanayek ◽  
Yao Xu ◽  
Aashish Lamichhane ◽  
Carl H. Johnson ◽  
Martin Egli
Keyword(s):  
Crystal Structure ◽  
Atpase Activity ◽  
Circadian Clock ◽  
Daily Cycle ◽  
Input Signals ◽  
Loop Regions ◽  
Insight Into ◽  
Shed Light ◽  
Clock Protein

A post-translational oscillator (PTO) composed of the proteins KaiA, KaiB and KaiC is at the heart of the cyanobacterial circadian clock. KaiC interacts with KaiA and KaiB over the daily cycle, and CII domains undergo rhythmic phosphorylation/dephosphorylation with a 24 h period. Both the N-terminal (CI) and C-terminal (CII) rings of KaiC exhibit ATPase activity. The CI ATPase proceeds in an input-independent fashion, but the CII ATPase is subject to metabolic input signals. The crystal structure of KaiC fromThermosynechococcus elongatusallows insight into the different anatomies of the CI and CII ATPases. Four consecutive arginines in CI (Arg linker) that connect the P-loop, CI subunits and CI and CII at the ring interface are primary candidates for the coordination of the CI and CII activities. The mutation of linker residues alters the period or triggers arhythmic behavior. Comparison between the CI and CII structures also reveals differences in loop regions that are key to KaiA and KaiB binding and activation of CII ATPase and kinase. Common packing features in KaiC crystals shed light on the KaiB–KaiC interaction.

scholarly journals Crystal Structure of Circadian Clock Protein KaiA fromSynechococcus elongatus

2004 ◽  
Vol 279 (19) ◽  
pp. 20511-20518 ◽  
Author(s):  
Sheng Ye ◽  
Ioannis Vakonakis ◽  
Thomas R. Ioerger ◽  
Andy C. LiWang ◽  
James C. Sacchettini
Keyword(s):  
Crystal Structure ◽  
Circadian Clock ◽  
Binding Site ◽  
Regulation Mechanism ◽  
Response Regulators ◽  
Dimer Interface ◽  
Helix Bundle ◽  
Bacterial Response ◽  
Four Helix Bundle ◽  
Clock Protein

The circadian clock found inSynechococcus elongatus, the most ancient circadian clock, is regulated by the interaction of three proteins, KaiA, KaiB, and KaiC. While the precise function of these proteins remains unclear, KaiA has been shown to be a positive regulator of the expression of KaiB and KaiC. The 2.0-Å structure of KaiA ofS. elongatusreported here shows that the protein is composed of two independently folded domains connected by a linker. The NH2-terminalpseudo-receiver domain has a similar fold with that of bacterial response regulators, whereas the COOH-terminal four-helix bundle domain is novel and forms the interface of the 2-fold-related homodimer. The COOH-terminal four-helix bundle domain has been shown to contain the KaiC binding site. The structure suggests that the KaiB binding site is covered in the dimer interface of the KaiA “closed” conformation, observed in the crystal structure, which suggests an allosteric regulation mechanism.

Sentence-Based Experience Logging in New Hearing Aid Users

2020 ◽  
Vol 29 (3S) ◽  
pp. 631-637
Author(s):  
Katja Lund ◽  
Rodrigo Ordoñez ◽  
Jens Bo Nielsen ◽  
Dorte Hammershøi
Keyword(s):  
Hearing Aid ◽  
Patient Experiences ◽  
Online Tool ◽  
Rehabilitation Process ◽  
Hearing Rehabilitation ◽  
Clinical Observations ◽  
Hearing Aid Use ◽  
Wide Range ◽  
Insight Into ◽  
Shed Light

Purpose The aim of this study was to develop a tool to gain insight into the daily experiences of new hearing aid users and to shed light on aspects of aided performance that may not be unveiled through standard questionnaires. Method The tool is developed based on clinical observations, patient experiences, expert involvement, and existing validated hearing rehabilitation questionnaires. Results An online tool for collecting data related to hearing aid use was developed. The tool is based on 453 prefabricated sentences representing experiences within 13 categories related to hearing aid use. Conclusions The tool has the potential to reflect a wide range of individual experiences with hearing aid use, including auditory and nonauditory aspects. These experiences may hold important knowledge for both the patient and the professional in the hearing rehabilitation process.

Aleksey Peshkov as an editor of Samarskaya Gazeta

2020 ◽  
pp. 128-138
Author(s):  
A. S. Bik-Bulatov
Keyword(s):  
Local History ◽  
Organizational Skills ◽  
First Time ◽  
New Evidence ◽  
Insight Into ◽  
Shed Light

The article uses little known letters of M. Gorky, many of which were published for the first time in 1997, as well as findings of Samara-based experts in local history to shed light on the writer’s work as editor-in-chief of the Samarskaya Gazeta newspaper in 1895. The researcher introduces hitherto unstudied reminiscences of the journalist D. Linyov (Dalin) about this period, which reference a letter by Gorky, now lost. The paper details a newly discovered episode of Gorky’s professional biography as a journalist: it concerns his campaign against a Samara ‘she-wolf,’ the madam of a local brothel A. Neucheva. Linyov’s reminiscences turn out to be an important and interesting source, offering an insight into the daily grind of the young editor Gorky, providing new evidence of his excellent organizational skills, and describing his moral and social stance. The author presents his work in the context of a recently initiated broader discussion about the need to map out all Russian periodicals for the period until 1917, as well as all research devoted to individual publications.

Crystal structure of KBSi3O8 isostructural with danburite

1993 ◽  
Vol 57 (386) ◽  
pp. 157-164 ◽  
Author(s):  
Mitsuyoshi Kimata
Keyword(s):  
Crystal Structure ◽  
Direct Method ◽  
Crystal Chemical ◽  
Chemical Formula ◽  
Crystal Chemical Formula ◽  
3 Dimensional ◽  
Tetrahedral Sites ◽  
Structural Types ◽  
Coupled Substitution ◽  
Insight Into

AbstractThe crystal structure of KBSi3O8 (orthorhombic, Pnam, with a = 8.683(1), b = 9.253(1), c = 8.272(1) Å,, V = 664.4(1) Å3, Z = 4) has been determined by the direct method applied to 3- dimensional rcflection data. The structure of a microcrystal with the dimensions 20 × 29 × 37 μm was refined to an unweightcd residual of R = 0.031 using 386 non-zero structure amplitudes. KBSi3O8 adopts a structure essentially different from recdmergneritc NaBSi3O8, with the low albite (NaAlSi3O8) structure, and isotypic with danburite CaB2Si2Os which has the same topology as paracelsian BaAl2Si2O8. The chenfical relationship between this sample and danburitc gives insight into a new coupled substitution; K+ + Si4+ = Ca2+ + B3+ in the extraframework and tetrahedral sites. The present occupancy refinement revealed partial disordering of B and Si atoms which jointly reside in two kinds of general equivalent points, T(1) and T(2) sites. Thus the expanded crystal-chemical formula can be written in the form K(B0.44Si0.56)2(B0.06Si0.94)2O8The systematic trend among crystalline compounds with the M+T3+T4+3O8 formula suggests that they exist in one of four structural types; the feldspar structures with T3+/T4+ ordered and/or disordered forms, and the paracelsian and the hollandite structures.

Insight into the physics of the 5f -band antiferromagnet U2Ni2Sn from the pressure dependence of crystal structure and electrical resistivity

2021 ◽  
Vol 103 (3) ◽  
Author(s):  
Silvie Maskova-Cerna ◽  
Alexandre Kolomiets ◽  
Jiri Prchal ◽  
Itzhak Halevy ◽  
Volodymyr Buturlim ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electrical Resistivity ◽  
Pressure Dependence ◽  
Insight Into
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