12 research outputs found
Kinetic regulation of multi-ligand binding proteins
Background: Second messengers, such as calcium, regulate the activity of multisite binding proteins in a concentration-dependent manner. For example, calcium binding has been shown to induce conformational transitions in the calcium-dependent protein calmodulin, under steady state conditions. However, intracellular concentrations of these second messengers are often subject to rapid change. The mechanisms underlying dynamic ligand-dependent regulation of multisite proteins require further elucidation. Results: In this study, a computational analysis of multisite protein kinetics in response to rapid changes in ligand concentrations is presented. Two major physiological scenarios are investigated: i) Ligand concentration is abundant and the ligand-multisite protein binding does not affect free ligand concentration, ii) Ligand concentration is of the same order of magnitude as the interacting multisite protein concentration and does not change. Therefore, buffering effects significantly influence the amounts of free ligands. For each of these scenarios the influence of the number of binding sites, the temporal effects on intermediate apo- and fully saturated conformations and the multisite regulatory effects on target proteins are investigated. Conclusions: The developed models allow for a novel and accurate interpretation of concentration and pressure jump-dependent kinetic experiments. The presented model makes predictions for the temporal distribution of multisite protein conformations in complex with variable numbers of ligands. Furthermore, it derives the characteristic time and the dynamics for the kinetic responses elicited by a ligand concentration change as a function of ligand concentration and the number of ligand binding sites. Effector proteins regulated by multisite ligand binding are shown to depend on ligand concentration in a highly nonlinear fashion
Effects Of Different Cavity Disinfectants On Shear Bond Strength Of A Silorane-Based Resin Composite
Scopu
The CMS Tracker operation and performance at the Magnet Test and Cosmic Challenge
During summer 2006 a fraction of the CMS silicon strip tracker was operated in a comprehensive slice test called the Magnet Test and Cosmic Challenge (MTCC). At the MTCC, cosmic rays detected in the muon chambers were used to trigger the readout of all CMS sub-detectors in the general data acquisition system and in the presence of the 4 T magnetic field produced by the CMS superconducting solenoid. This document describes the operation of the Tracker hardware and software prior, during and after data taking. The performance of the detector as resulting from the MTCC data analysis is also presented. © 2008 IOP Publishing Ltd and SISSA.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Stand-alone cosmic muon reconstruction before installation of the CMS silicon strip tracker
The subsystems of the CMS silicon strip tracker were integrated and
commissioned at the Tracker Integration Facility (TIF) in the period from
November 2006 to July 2007. As part of the commissioning, large samples of
cosmic ray data were recorded under various running conditions in the absence
of a magnetic field. Cosmic rays detected by scintillation counters were used
to trigger the readout of up to 15% of the final silicon strip detector, and
over 4.7 million events were recorded. This document describes the cosmic track
reconstruction and presents results on the performance of track and hit
reconstruction as from dedicated analyses.Comment: Added missing LaTex command / no change in contents w.r.t. v