Energy minimization with loop fusion and multi-functional-unit scheduling for multidimensional DSP

2008 ◽  
Vol 68 (4) ◽  
pp. 443-455 ◽  
Author(s):  
Meikang Qiu ◽  
Edwin H.-M. Sha ◽  
Meilin Liu ◽  
Man Lin ◽  
Shaoxiong Hua ◽  
...  
Keyword(s):  
Energy Minimization ◽  
Functional Unit ◽  
Loop Fusion

Comments on the Antonow and interfacial interaction rules

1990 ◽  
Vol 55 (5) ◽  
pp. 1143-1148 ◽  
Author(s):  
Jan Kloubek
Keyword(s):  
Free Energy ◽  
Energy Minimization ◽  
Interfacial Interaction ◽  
Aliphatic Hydrocarbon ◽  
Theoretical Base ◽  
Water Interface ◽  
Free Energy Minimization ◽  
Interaction Rule

Results presented for the aliphatic hydrocarbon-water interface show that the recent hypothesis of the free energy minimization called interfacial interaction rule, which was suggested as a theoretical base of the Antonow rule, cannot be generally valid.

scholarly journals B0AT1 amino acid transporter complexed with SARS-CoV-2 receptor ACE2 forms a heterodimer functional unit: in situ conformation using radiation inactivation analysis

Function ◽  
2021 ◽  
Author(s):  
Bruce R Stevens ◽  
J Clive Ellory ◽  
Robert L Preston
Keyword(s):  
Amino Acid ◽  
Membrane Trafficking ◽  
Functional Unit ◽  
Membrane Vesicles ◽  
High Energy ◽  
Amino Acid Transporter ◽  
Neutral Amino Acid ◽  
Transport Activity ◽  
Acid Transporter

Abstract The SARS-CoV-2 receptor, Angiotensin Converting Enzyme-2 (ACE2), is expressed at levels of greatest magnitude in the small intestine as compared to all other human tissues. Enterocyte ACE2 is co-expressed as the apical membrane trafficking partner obligatory for expression and activity of the B0AT1 sodium-dependent neutral amino acid transporter. These components are assembled as an [ACE2: B0AT1]2 dimer-of-heterodimers quaternary complex that putatively steers SARS-CoV-2 tropism in the gastrointestinal (GI) tract. GI clinical symptomology is reported in about half of COVID-19 patients, and can be accompanied by gut shedding of virion particles. We hypothesized that within this 4-mer structural complex, each [ACE2: B0AT1] heterodimer pair constitutes a physiological “functional unit.” This was confirmed experimentally by employing purified lyophilized enterocyte brush border membrane vesicles that were exposed to increasing doses of high-energy electron radiation from a 16 MeV linear accelerator. Based on established target theory, the results indicated the presence of Na+-dependent neutral amino acid influx transport activity functional unit with target size mw = 183.7 ± 16.8 kDa in situ in intact apical membranes. Each thermodynamically stabilized [ACE2: B0AT1] heterodimer functional unit manifests the transport activity within the whole ∼345 kDa [ACE2: B0AT1]2 dimer-of-heterodimers quaternary structural complex. The results are consistent with our prior molecular docking modeling and gut-lung axis approaches to understanding COVID-19. These findings advance the understanding of the physiology of B0AT1 interaction with ACE2 in the gut, and thereby potentially contribute to translational developments designed to treat or mitigate COVID-19 variant outbreaks and/or GI symptom persistence in long-haul Post-Acute Sequelae of SARS-CoV-2 (PASC).

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