Conformational effects on the Circular Dichroism of Human Carbonic Anhydrase II: a multilevel computational study

Circular Dichroism (CD) spectroscopy is a powerful method for investigating conformational changes in proteins and therefore has numerous applications in structural and molecular biology. Here a computational investigation of the CD spectrum of the Human Carbonic Anhydrase II (HCAII), with main focus on the near-UV CD spectra of the wild-type enzyme and it seven tryptophan mutant forms, is presented and compared to experimental studies. Multilevel computational methods (Molecular Dynamics, Semiempirical Quantum Mechanics, Time-Dependent Density Functional Theory) were applied in order to gain insight into the mechanisms of interaction between the aromatic chromophores within the protein environment and understand how the conformational flexibility of the protein influences these mechanisms. The analysis suggests that combining CD semi empirical calculations, crystal structures and molecular dynamics (MD) could help in achieving a better agreement between the computed and experimental protein spectra and provide some unique insight into the dynamic nature of the mechanisms of chromophore interactions

Theory of Ion-Transfer Processes at Electrodes and Solution

An extensive review is given of the author\u27s theory of ion- transfer processes at electrodes and in solution. The exposition concerns only those features which are independent of any assumptions about the mechan1sm of the particular process. The theory allows extension to many specific cases by adoption of simple models

How does conformational flexibility influence key structural features involved in activation of anaplastic lymphoma kinase?

Anaplastic Lymphoma Kinase (ALK) plays a major role in developing tumor processes and therefore has emerged as a validated therapeutic target. Applying atomistic molecular dynamics simulations on the wild type enzyme and the nine most frequently occurring and clinically important activation mutants we revealed important conformational effects on key interactions responsible for the activation of the enzyme

Weak electricity of the Nucleon in the Chiral Quark-Soliton Model

The induced pseudotensor constant (weak electricity) of the nucleon is calculated in the framework of the chiral quark soliton model. This quantity originates from the G-parity violation and hence is proportional to $m_u-m_d$. We obtain for $m_u-m_d=-5 MeV$ a value of $g_T/g_A =-0.0038$.Comment: The final version. Accepted for publication in Phys. Rev.

Principal component analysis for the detection and assessment of T-wave alternans

Abstract T wave alternans (TWA) is an electrophisiologic Introduction T-wave alternans is a prognostic indicator of preceding episodes of Torsade de Pointes life-threatening arrhythmia TWA appears in the electrocardiogram as a consistent fluctuation in the repolarization morphology on everyother beat basis. The computerized ECG analysis led to the discovery, and routine clinical assessment, of invisible to the naked eye microvolt TWA Heart rate alone appears to be the main factor of determining the onset of TWA during submaximal exercise stress tests A variety of algorithms for detecting and quantifying TWA have been proposed, employing techniques as spectral analysis, complex demodulation, zero-crossings counting in a series of correlation coefficients, KarhunenLoève transform, low-pass Capon filtering, Poincaré mapping, periodicity transforms, statistical tests, modified moving average, Laplacian likelihood ratio, etc. A review by Martínez and Olmos [8] highlights the need for methodological systematization effort in characterization and comparison of the different methods. A multilead approach to T-wave alternans detection combining PCA and the Laplacian likelihood ratio method is proposed by Monasterio and Martínez The aim of this study is to assess the detection and quantification of TWA, by the performance of two combined methods: Twave amplitude statistical analysis and PCA in the framework of PhysioNet/Computers in Cardiology 2008 Challenge [10]. Methods A set of 100 ECG recordings were selected and collected in the framework of the Challenge [10] in order to test different algorithms for the detection and the quantification of TWA. These recordings consisted of 16 with 2 leads, 12 with 3 leads and the remaining 72 recordings with 12 leads

Self-Consistent Pushing and Cranking Corrections to the Meson Fields of the Chiral Quark-Loop Soliton

We study translational and spin-isospin symmetry restoration for the two-flavor chiral quark-loop soliton. Instead of a static soliton at rest we consider a boosted and rotating hedgehog soliton. Corrected classical meson fields are obtained by minimizing a corrected energy functional which has been derived by semi-classical methods ('variation after projection'). We evaluate corrected meson fields in the region 300 MeV \le M \le 600 MeV of constituent quark masses M and compare them with the uncorrected fields. We study the effect of the corrections on various expectation values of nuclear observables such as the root-mean square radius, the axial-vector coupling constant, magnetic moments and the delta-nucleon mass splitting.Comment: 19 pages, LaTeX, 7 postscript figures included using 'psfig.sty', to appear in Int.J.Mod.Phys.