We propose a novel Metropolis Monte Carlo procedure for protein modeling and analyze the influence of hydrogen bonding on the distribution of polyalanine conformations. We use an atomistic model of the polyalanine chain with rigid and planar polypeptide bonds, and elastic alpha carbon valence geometry. We adopt a simplified energy function in which only hard-sphere repulsion and hydrogen bonding interactions between the atoms are considered. Our Metropolis Monte Carlo procedure utilizes local crankshaft moves and is combined with parallel tempering to exhaustively sample the conformations of 16-mer polyalanine. We confirm that Flory's isolated-pair hypothesis (the steric independence between the dihedral angles of individual amino acids) does not hold true in long polypeptide chains. In addition to 3(10)- and alpha-helices, we identify a kink stabilized by 2 hydrogen bonds with a shared acceptor as a common structural motif. Varying the strength of hydrogen bonds, we induce the helix-coil transition in the model polypeptide chain. We compare the propensities for various hydrogen bonding patterns and determine the degree of cooperativity of hydrogen bond formation in terms of the Hill coefficient. The observed helix-coil transition is also quantified according to Zimm-Bragg theory.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/prot.20513 | DOI Listing |
Nanoscale
January 2025
Photon Science Research Center for Carbon Dioxide, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
Oxygen vacancies (V's) are of paramount importance in influencing the properties and applications of ceria (CeO). Yet, comprehending the distribution and nature of V's poses a significant challenge due to the vast number of electronic configurations and intricate many-body interactions among V's and polarons (Ce ions). In this study, we established a cluster expansion model based on first-principles calculations and statistical learning to decouple the interactions among the Ce ions and V's, thereby circumventing the limitations associated with sampling electronic configurations.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Department of Mechanical Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan.
Unbalance faults are among the common causes of interruptions and unexpected failures in rotary systems. Therefore, monitoring unbalance faults is essential for predictive maintenance. While conventional time-invariant mathematical models can assess the impact of these faults, they often rely on proper assumptions of system factors like bearing stiffness and damping characteristics.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
In this work, we propose a path integral Monte Carlo approach based on discretized continuous degrees of freedom and rejection-free Gibbs sampling. The ground state properties of a chain of planar rotors with dipole-dipole interactions are used to illustrate the approach. Energetic and structural properties are computed and compared to exact diagonalization and numerical matrix multiplication for N ≤ 3 to assess the systematic Trotter factorization error convergence.
View Article and Find Full Text PDFAust N Z J Stat
September 2024
Department of Mathematical Sciences, Michigan Technological University, Houghton, MI, 49931, USA.
Multivariate longitudinal ordinal and continuous data exist in many scientific fields. However, it is a rigorous task to jointly analyse them due to the complicated correlated structures of those mixed data and the lack of a multivariate distribution. The multivariate probit model, assuming there is a multivariate normal latent variable for each multivariate ordinal data, becomes a natural modeling choice for longitudinal ordinal data especially for jointly analysing with longitudinal continuous data.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Institut für Theoretische Physik, Universität Leipzig, IPF 231101, 04081 Leipzig, Germany.
We investigate the aging properties of phase-separation kinetics following quenches from T=∞ to a finite temperature below T_{c} of the paradigmatic two-dimensional conserved Ising model with power-law decaying long-range interactions ∼r^{-(2+σ)}. Physical aging with a power-law decay of the two-time autocorrelation function C(t,t_{w})∼(t/t_{w})^{-λ/z} is observed, displaying a complex dependence of the autocorrelation exponent λ on σ. A value of λ=3.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!