STUDIES OF FINDING LOW ENERGY CONFIGURATIONS IN OFF-LATTICE PROTEIN MODELS

2006 ◽  
Vol 05 (03) ◽  
pp. 587-594 ◽  
Author(s):  
JINGFA LIU ◽  
WENQI HUANG

We studied two three-dimensional off-lattice protein models with two species of monomers, hydrophobic and hydrophilic. Low energy configurations in both models were optimized using the energy landscape paving (ELP) method and subsequent gradient descent. The numerical results show that the proposed methods are very promising for finding the ground states of proteins. For all sequences with lengths 13 ≤ n ≤ 55, the algorithm finds states with lower energy than previously proposed putative ground states.

2007 ◽  
Vol 18 (01) ◽  
pp. 99-106 ◽  
Author(s):  
ETHEM AKTÜRK ◽  
HANDAN ARKIN ◽  
TARIK ÇELİK

We have performed multicanonical simulations of hydrophobic-hydrophilic heteropolymers with a simple effective, coarse-grained off-lattice model to study the structure and the topology of the energy surface. The multicanonical method samples the whole rugged energy landscape, in particular the low-energy part, and enables one to better understand the critical behaviors and visualize the folding pathways of the considered protein model.


2004 ◽  
Vol 15 (02) ◽  
pp. 223-231 ◽  
Author(s):  
HANDAN ARKIN

The three-dimensional structures of the heptapeptide deltorphin ( H - Tyr 1- D - Met 2- Phe 3- His 4- Leu 5- Met 6- Asp 7- NH 2) are studied in aqueous solution using Energy Landscape Paving (ELP) method. The effect of a solvation energy term on the conformations are determined by analyzing Ramachandran plots. The structures are compared with experimental NMR data. By minimizing the energy structures, the low-energy microstates of the molecule in aqueous solution are determined.


2003 ◽  
Vol 14 (07) ◽  
pp. 985-991 ◽  
Author(s):  
HANDAN ARKIN ◽  
TARIK ÇELIK

We propose a hybrid algorithm, which combines the features of the energy landscape paving (ELP) and Monte Carlo Minimization (MCM) methods. We have tested its performance in studying the low-energy conformations of the heptapeptide deltorphin.


2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Alejandro Perdomo-Ortiz ◽  
Neil Dickson ◽  
Marshall Drew-Brook ◽  
Geordie Rose ◽  
Alán Aspuru-Guzik

2020 ◽  
Vol 117 (26) ◽  
pp. 14987-14995 ◽  
Author(s):  
Ratan Othayoth ◽  
George Thoms ◽  
Chen Li

Effective locomotion in nature happens by transitioning across multiple modes (e.g., walk, run, climb). Despite this, far more mechanistic understanding of terrestrial locomotion has been on how to generate and stabilize around near–steady-state movement in a single mode. We still know little about how locomotor transitions emerge from physical interaction with complex terrain. Consequently, robots largely rely on geometric maps to avoid obstacles, not traverse them. Recent studies revealed that locomotor transitions in complex three-dimensional (3D) terrain occur probabilistically via multiple pathways. Here, we show that an energy landscape approach elucidates the underlying physical principles. We discovered that locomotor transitions of animals and robots self-propelled through complex 3D terrain correspond to barrier-crossing transitions on a potential energy landscape. Locomotor modes are attracted to landscape basins separated by potential energy barriers. Kinetic energy fluctuation from oscillatory self-propulsion helps the system stochastically escape from one basin and reach another to make transitions. Escape is more likely toward lower barrier direction. These principles are surprisingly similar to those of near-equilibrium, microscopic systems. Analogous to free-energy landscapes for multipathway protein folding transitions, our energy landscape approach from first principles is the beginning of a statistical physics theory of multipathway locomotor transitions in complex terrain. This will not only help understand how the organization of animal behavior emerges from multiscale interactions between their neural and mechanical systems and the physical environment, but also guide robot design, control, and planning over the large, intractable locomotor-terrain parameter space to generate robust locomotor transitions through the real world.


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