scholarly journals Functional Relevance of AcrB Trimerization in Pump Assembly and Substrate Binding

PLoS ONE ◽  
2014 ◽  
Vol 9 (2) ◽  
pp. e89143 ◽  
Author(s):  
Wei Lu ◽  
Meng Zhong ◽  
Qian Chai ◽  
Zhaoshuai Wang ◽  
Linliang Yu ◽  
...  
Keyword(s):  
Substrate Binding ◽  
Functional Relevance ◽  
Pump Assembly

scholarly journals Multiple Extracellular Loops Contribute to Substrate Binding and Transport by the Escherichia coli Cobalamin Transporter BtuB

2005 ◽  
Vol 187 (5) ◽  
pp. 1732-1739 ◽  
Author(s):  
Cynthia A. Fuller-Schaefer ◽  
Robert J. Kadner
Keyword(s):  
Escherichia Coli ◽  
Substrate Binding ◽  
High Specificity ◽  
Globular Domain ◽  
Colicin E1 ◽  
Extracellular Loops ◽  
Crystallographic Structures ◽  
Functional Relevance ◽  
Almost All ◽  
Colicin E3

ABSTRACT The Escherichia coli outer membrane TonB-dependent transporters for iron complexes and cobalamins recognize their multiple and diverse substrates with high specificity and affinity. The X-ray crystallographic structures of several transporters show that the substrate-binding surfaces are comprised of residues from the internal globular domain and multiple extracellular loops. The extracellular loops on the N-terminal half of the transmembrane beta-barrel of the cobalamin transporter BtuB participate in binding of the cofactor calcium atoms and undergo substantial conformation changes upon substrate binding. The functional relevance of the five C-terminal loops was examined by examining the effects of short in-frame deletions. Each loop contributed in different ways to the binding of BtuB substrates. Deletions in loops 7, 8, 9, and 11 strongly decreased cobalamin binding and transport, whereas deletions in loops 8, 9, and 10 affected binding and entry of phage BF23. None of the loops were essential for the action of colicin E1 or E3, which is consistent with the crystallographic observation that the colicin E3 receptor-binding domain can contact almost all of the loops. A deletion in loop 9 or 11 eliminated the ability of cobalamin to inhibit the action of colicin E1. These phenotypes show that there are multiple independent binding elements and point out similarities and differences in binding properties among the TonB-dependent transporters.

Fibronexus-Like Adhesion Sites are Present at the Invasive Zones of Human Epidermoid Carcinomas

1982 ◽  
Vol 40 ◽  
pp. 106-109
Author(s):  
Irwin I. Singer
Keyword(s):  
Cell Cycle ◽  
Serum Concentration ◽  
Substrate Binding ◽  
High Serum ◽  
Adhesion Sites ◽  
Substrate Adhesion ◽  
Focal Contacts ◽  
Adhesion Complex ◽  
Low Serum

Our previous results indicate that two types of fibronectin-cytoskeletal associations may be formed at the fibroblast surface: dorsal matrixbinding fibronexuses generated in high serum (5% FBS) cultures, and ventral substrate-adhering units formed in low serum (0.3% FBS) cultures. The substrate-adhering fibronexus consists of at least vinculin (VN) and actin in its cytoplasmic leg, and fibronectin (FN) as one of its major extracellular components. This substrate-adhesion complex is localized in focal contacts, the sites of closest substratum approach visualized with interference reflection microscopy, which appear to be the major points of cell-tosubstrate adhesion. In fibroblasts, the latter substrate-binding complex is characteristic of cultures that are arrested at the G1 phase of the cell cycle due to the low serum concentration in their medium. These arrested fibroblasts are very well spread, flattened, and immobile.

Assessing Stressors Related to Migration in Patients With Psychiatric Disorders

2012 ◽  
Vol 28 (4) ◽  
pp. 262-269 ◽  
Author(s):  
Matthias Johannes Müller ◽  
Suzan Kamcili-Kubach ◽  
Songül Strassheim ◽  
Eckhardt Koch
Keyword(s):  
Interrater Reliability ◽  
Item Analysis ◽  
Global Assessment Of Functioning ◽  
Family Conflicts ◽  
Response Options ◽  
Reliability Indices ◽  
Dsm Iv ◽  
Functional Relevance ◽  
Sum Scores ◽  
Gaf Scores

A 10-item instrument for the assessment of probable migration-related stressors was developed based on previous work (MIGSTR10) and interrater reliability was tested in a chart review study. The MIGSTR10 and nine nonspecific stressors of the DSM-IV Axis IV (DSMSTR9) were put into a questionnaire format with categorical and dimensional response options. Charts of 100 inpatients (50 Turkish migrants [MIG], 50 native German patients [CON]) with affective or anxiety disorder were reviewed by three independent raters and MIGSTR10, DSMSTR9, and Global Assessment of Functioning scale (GAF) scores were obtained. Interrater reliability indices (ICC) of items and sum scores were calculated. The prevalence of single migration-related stressors in MIG ranged from 15% to 100% (CON 0–92%). All items of the MIGSTR10 (ICC 0.58–0.92) and the DSMSTR9 (ICC 0.56–0.96) reached high to very high interrater agreement (p < .0005). The item analysis of the MIGSTR10 revealed sufficient internal consistency (Cronbach’s α = 0.68/0.69) and only one item (“family conflicts”) without substantial correlation with the remaining scale. Correlation analyses showed a significant overlap of dimensional MIGSTR10 scores (r² = 0.25; p < .01) and DSMSTR9 scores (r² = 9%; p < .05) with GAF scores in MIG indicating functional relevance. MIGSTR10 is considered a feasible, economic, and reliable instrument for the assessment of stressors potentially related to migration.

Copper–oxygen Dynamics in Tyrosinase

2019 ◽  
Author(s):  
Nobutaka Fujieda ◽  
Sachiko Yanagisawa ◽  
Minoru Kubo ◽  
Genji Kurisu ◽  
Shinobu Itoh
Keyword(s):  
Catalytic Mechanism ◽  
Substrate Binding ◽  
Active Form ◽  
Copper Ion ◽  
Atomic Resolution ◽  
Oxygen Species ◽  
X Ray ◽  
Oxygen Dynamics ◽  
Insight Into ◽  
Copper Centre

To unveil the activation of dioxygen on the copper centre (Cu<sub>2</sub>O<sub>2</sub>core) of tyrosinase, we performed X-ray crystallograpy with active-form tyrosinase at near atomic resolution. This study provided a novel insight into the catalytic mechanism of the tyrosinase, including the rearrangement of copper-oxygen species as well as the intramolecular migration of copper ion induced by substrate-binding.<br>

A study into the feasibility of using the oxygen-hydrocarbon engine 11D58M as a basis for development of a high-performance multifunctional gas-generatorless rocket engine with oxygen cooling

2019 ◽  
pp. 67-80
Author(s):  
Boris A. Sokolov ◽  
Nikolay N. Tupitsyn
Keyword(s):  
Film Cooling ◽  
High Performance ◽  
Rocket Engine ◽  
Hydrocarbon Fuel ◽  
Gas Generator ◽  
Automatic Equipment ◽  
The Us ◽  
Upper Stage ◽  
Pump Assembly ◽  
Turbo Pump

The paper presents results of engineering studies and research and development efforts at RSC Energia to analyze and prove the feasibility of using the mass-produced oxygen-hydrocarbon engine 11D58M with 8.5 ton-force thrust as a basis for development of a high-performance multifunctional rocket engine with oxygen cooling and 5 ton-force thrust, which is optimal for upper stages (US), embodying a system that does not include a gas generator. The multi-functionality of the engine implies including in it additional units supporting some functions that are important for US, such as feeding propellant from US tanks to the engine after flying in zero gravity, autonomous control of the engine automatic equipment to support its firing, shutdown, adjustments during burn and emergency protection in case of off-nominal operation, as well as generating torques for controlling the US attitude and stabilizing it during coasting, etc. Replacing conventional engine chamber cooling that uses high-boiling hydrocarbon fuel with the innovative oxygen cooling makes it possible to get rid of the internal film cooling circuits and eliminate their attendant losses of fuel, while the use of the oxygen gasified in the cooling circuit of the chamber to drive the turbo pump assembly permits to design an engine that does not have a gas generator. Key words: Multifunctional rocket engine, oxygen cooling, gas-generatorless design, upper stage.

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