Experiments to search for a substrate state for3he adjacent to surfaces in3He-4He mixtures

1995 ◽  
Vol 101 (1-2) ◽  
pp. 231-236 ◽  
Author(s):  
P. A. Sheldon ◽  
J. P. Vithayathil ◽  
R. B. Hallock
Keyword(s):  
Substrate State

Effect of the substrate state on the microstructure and tribological properties of sulphide layer on 1045 steel

2000 ◽  
Vol 161 (1-2) ◽  
pp. 170-177 ◽  
Author(s):  
Ning Zhang ◽  
Da-Ming Zhuang ◽  
Jia-Jun Liu ◽  
Xiao-Dong Fang ◽  
Ming-Xi Guan
Keyword(s):  
Tribological Properties ◽  
1045 Steel ◽  
Substrate State

scholarly journals Structural and Binding Analysis of Pyrimidinol Carboxylic Acid andN-Hydroxy Quinazolinedione HIV-1 RNase H Inhibitors

2011 ◽  
Vol 55 (6) ◽  
pp. 2905-2915 ◽  
Author(s):  
Eric B. Lansdon ◽  
Qi Liu ◽  
Stephanie A. Leavitt ◽  
Mini Balakrishnan ◽  
Jason K. Perry ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Metal Ions ◽  
Active Site ◽  
Water Environment ◽  
Divalent Metal ◽  
Rnase H ◽  
Accurate Assessment ◽  
Divalent Metal Ions ◽  
Substrate State ◽  
Hiv 1

ABSTRACTHIV-1 RNase H breaks down the intermediate RNA-DNA hybrids during reverse transcription, requiring two divalent metal ions for activity. Pyrimidinol carboxylic acid andN-hydroxy quinazolinedione inhibitors were designed to coordinate the two metal ions in the active site of RNase H. High-resolution (1.4 Å to 2.1 Å) crystal structures were determined with the isolated RNase H domain and reverse transcriptase (RT), which permit accurate assessment of the metal and water environment at the active site. The geometry of the metal coordination suggests that the inhibitors mimic a substrate state prior to phosphodiester catalysis. Surface plasmon resonance studies confirm metal-dependent binding to RNase H and demonstrate that the inhibitors do not bind at the polymerase active site of RT. Additional evaluation of the RNase H site reveals an open protein surface with few additional interactions to optimize active-site inhibitors.

scholarly journals Synthesis of bi-substrate state mimics of dihydropteroate synthase as potential inhibitors and molecular probes

2011 ◽  
Vol 19 (3) ◽  
pp. 1298-1305 ◽  
Author(s):  
Jianjun Qi ◽  
Kristopher G. Virga ◽  
Sourav Das ◽  
Ying Zhao ◽  
Mi-Kyung Yun ◽  
...  
Keyword(s):  
Molecular Probes ◽  
Dihydropteroate Synthase ◽  
Potential Inhibitors ◽  
Substrate State

Influences of Inflow Mode on Nutrient Removal Efficiency in a New SBR System

2010 ◽  
Vol 26-28 ◽  
pp. 553-558
Author(s):  
Ang Li ◽  
Yan Qiu Zhang ◽  
Yan Li ◽  
Zhi Jun Diao
Keyword(s):  
Removal Efficiency ◽  
Distribution Ratio ◽  
Nutrient Removal ◽  
Municipal Sewage ◽  
Removal Rates ◽  
Whole Process ◽  
High Nutrient ◽  
Nutrient Removal Efficiency ◽  
Substrate State ◽  
Sludge Concentration

With influent distribution, high sludge concentration and low substrate state are carried out in ECOSUNIDE technics, bring in high nutrient removal efficiency. The “influent distribution” was introduced into conventional SBR for the treatment of municipal sewage, aiming to improve the nutrient removal efficiency. The whole process included an anaerobic and multiple anoxic/ aerobic units. The distribution ratios and modes are studied in this paper. The results show that the average sludge concentration reaches high to 6000mg/L. The influent mode has significant influences on the nutrient removal in the new SBR system. The mode of instantaneous influent in anaerobic stage and intermittent in frequent aeration stage is optimal, with the distribution ratio of 0.4/0.6, and the removal rates of NH3-N, TN and TP reach 99%, 87%, and 98%, respectively.

Possible observation of the substrate state in3He-4He mixture films

1994 ◽  
Vol 194-196 ◽  
pp. 853-854 ◽  
Author(s):  
W.A. Draisma ◽  
M.E.W. Eggenkamp ◽  
P.W.H. Pinkse ◽  
R. Jochemsen ◽  
G. Frossati
Keyword(s):  
Substrate State

scholarly journals Delicate structural coordination of the Severe Acute Respiratory Syndrome coronavirus Nsp13 upon ATP hydrolysis

2019 ◽  
Vol 47 (12) ◽  
pp. 6538-6550 ◽  
Author(s):  
Zhihui Jia ◽  
Liming Yan ◽  
Zhilin Ren ◽  
Lijie Wu ◽  
Jin Wang ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Rna Polymerase ◽  
Drug Targets ◽  
Atp Hydrolysis ◽  
Helicase Activity ◽  
Product State ◽  
Potential Drug ◽  
Rna Dependent Rna Polymerase ◽  
Potential Drug Targets ◽  
Substrate State

Abstract To date, an effective therapeutic treatment that confers strong attenuation toward coronaviruses (CoVs) remains elusive. Of all the potential drug targets, the helicase of CoVs is considered to be one of the most important. Here, we first present the structure of the full-length Nsp13 helicase of SARS-CoV (SARS-Nsp13) and investigate the structural coordination of its five domains and how these contribute to its translocation and unwinding activity. A translocation model is proposed for the Upf1-like helicase members according to three different structural conditions in solution characterized through H/D exchange assay, including substrate state (SARS-Nsp13-dsDNA bound with AMPPNP), transition state (bound with ADP-AlF4−) and product state (bound with ADP). We observed that the β19–β20 loop on the 1A domain is involved in unwinding process directly. Furthermore, we have shown that the RNA dependent RNA polymerase (RdRp), SARS-Nsp12, can enhance the helicase activity of SARS-Nsp13 through interacting with it directly. The interacting regions were identified and can be considered common across CoVs, which provides new insights into the Replication and Transcription Complex (RTC) of CoVs.

scholarly journals Specific accumulation of 17α-hydroxyprogesterone in microsomal membranes during the process of cytochrome P-450(C-17)-catalysed androgen biosynthesis. A dynamic study of intermediate formation and turnover

1988 ◽  
Vol 256 (1) ◽  
pp. 53-59 ◽  
Author(s):  
N Kühn-Velten ◽  
M Lessmann ◽  
M E Förster ◽  
W Staib
Keyword(s):  
Direct Evidence ◽  
Intermediate Formation ◽  
Specific Accumulation ◽  
Membrane Compartment ◽  
Microsomal Membranes ◽  
Double Label ◽  
Double Substrate ◽  
Label Distribution ◽  
Cytochrome P 450 ◽  
Substrate State

A complete dynamic analysis of cytochrome P-450(C-17)-catalysed androgen biosynthesis from a single dose of progesterone and 17 alpha-hydroxyprogesterone in a double-label double-substrate experiment was performed in order to elucidate the controversial intermediacy of 17 alpha-hydroxyprogesterone. Label distribution within the steroid fractions as well as in the membrane and buffer compartments yields direct evidence that the endogenously formed 17 alpha-hydroxyprogesterone (which is in an ‘intermediate state’) accumulates to a higher degree in microsomal membranes than does the exogenously added 17 alpha-hydroxyprogesterone (which is in a ‘substrate state’) under certain conditions. It is also demonstrated that endogenously formed 17 alpha-hydroxyprogesterone may partly leave the membrane compartment (in terms of a ‘leakage’ or ‘overflow’ phenomenon) and is then able to equilibrate with the pool of exogenously added 17 alpha-hydroxyprogesterone. Since only the label distribution in the membrane-associated (but not always in the aqueous) 17 alpha-hydroxyprogesterone pool corresponds to the label distribution in the androgen fraction, it is concluded that only the membrane-associated 17 alpha-hydroxyprogesterone pool is directly accessible to cytochrome P-450(C-17)-catalysed conversion into androgens.

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