Principal component analysis on a torus: Theory and application to protein dynamics

2017 ◽  
Vol 147 (24) ◽  
pp. 244101 ◽  
Author(s):  
Florian Sittel ◽  
Thomas Filk ◽  
Gerhard Stock
Keyword(s):  
Principal Component Analysis ◽  
Protein Dynamics ◽  
Principal Component ◽  
Component Analysis

Contact- and distance-based principal component analysis of protein dynamics

2015 ◽  
Vol 143 (24) ◽  
pp. 244114 ◽  
Author(s):  
Matthias Ernst ◽  
Florian Sittel ◽  
Gerhard Stock
Keyword(s):  
Principal Component Analysis ◽  
Protein Dynamics ◽  
Principal Component ◽  
Component Analysis

scholarly journals Principal Component Analysis and Long Time Protein Dynamics

1996 ◽  
Vol 100 (7) ◽  
pp. 2567-2572 ◽  
Author(s):  
M. A. Balsera ◽  
W. Wriggers ◽  
Y. Oono ◽  
K. Schulten
Keyword(s):  
Principal Component Analysis ◽  
Protein Dynamics ◽  
Principal Component ◽  
Component Analysis ◽  
Long Time

scholarly journals Comparison between slow, anisotropic LE4PD fluctuations and the Principal Component Analysis modes of Ubiquitin

2021 ◽  
Author(s):  
Eric R Beyerle ◽  
Marina G Guenza
Keyword(s):  
Principal Component Analysis ◽  
Free Energy ◽  
Protein Dynamics ◽  
Large Scale ◽  
Principal Component ◽  
Component Analysis ◽  
Hydrodynamic Interactions ◽  
Complete Analysis ◽  
Energy Barriers ◽  
Protein Motion

Proteins' biological function and folding mechanisms are often guided by large-scale, slow motions, which involve crossing high energy barriers. In a simulation trajectory, these slow fluctuations are commonly identified using a principal component analysis (PCA). Despite the popularity of this method, a complete analysis of its predictions based on the physics of protein motion has been so far limited. This study formally connects the PCA to a Langevin model of protein dynamics and analyzes the contributions of energy barriers and hydrodynamic interactions to the slow PCA modes of motion. To do so, we introduce an anisotropic extension of the Langevin Equation for Protein Dynamics, called the LE4PD-XYZ, which formally connects to the PCA 'essential dynamics'. The LE4PD-XYZ is an accurate coarse-grained diffusive method to model protein motion, which describes anisotropic fluctuations in the protein's alpha-carbons. The LE4PD accounts for hydrodynamic effects and mode-dependent free-energy barriers. This study compares large-scale anisotropic fluctuations identified by the LE4PD-XYZ to the mode-dependent PCA's predictions, starting from a microsecond-long alpha-carbon molecular dynamics atomistic trajectory of the protein ubiquitin. We observe that the inclusion of free-energy barriers and hydrodynamic interactions has important effects on the identification and timescales of ubiquitin's slow modes.

A German version of the Intermittent Claudication Questionnaire (ICQ): cultural adaptation and validation

VASA ◽  
2012 ◽  
Vol 41 (5) ◽  
pp. 333-342 ◽  
Author(s):  
Kirchberger ◽  
Finger ◽  
Müller-Bühl
Keyword(s):  
Principal Component Analysis ◽  
Intermittent Claudication ◽  
Completion Time ◽  
Short Form ◽  
Principal Component ◽  
Component Analysis ◽  
German Version ◽  
Average Completion Time ◽  
Sf 36 ◽  
Related Quality

Background: The Intermittent Claudication Questionnaire (ICQ) is a short questionnaire for the assessment of health-related quality of life (HRQOL) in patients with intermittent claudication (IC). The objective of this study was to translate the ICQ into German and to investigate the psychometric properties of the German ICQ version in patients with IC. Patients and methods: The original English version was translated using a forward-backward method. The resulting German version was reviewed by the author of the original version and an experienced clinician. Finally, it was tested for clarity with 5 German patients with IC. A sample of 81 patients were administered the German ICQ. The sample consisted of 58.0 % male patients with a median age of 71 years and a median IC duration of 36 months. Test of feasibility included completeness of questionnaires, completion time, and ratings of clarity, length and relevance. Reliability was assessed through a retest in 13 patients at 14 days, and analysis of Cronbach’s alpha for internal consistency. Construct validity was investigated using principal component analysis. Concurrent validity was assessed by correlating the ICQ scores with the Short Form 36 Health Survey (SF-36) as well as clinical measures. Results: The ICQ was completely filled in by 73 subjects (90.1 %) with an average completion time of 6.3 minutes. Cronbach’s alpha coefficient reached 0.75. Intra-class correlation for test-retest reliability was r = 0.88. Principal component analysis resulted in a 3 factor solution. The first factor explained 51.5 of the total variation and all items had loadings of at least 0.65 on it. The ICQ was significantly associated with the SF-36 and treadmill-walking distances whereas no association was found for resting ABPI. Conclusions: The German version of the ICQ demonstrated good feasibility, satisfactory reliability and good validity. Responsiveness should be investigated in further validation studies.

Sign in / Sign up

Export Citation Format

Share Document