ANCA Kidney Risk Score Performance in a German Cohort of Patients with Histologically Confirmed ANCA-Associated Renal Vasculitis.

Key Points: The revised ANCA kidney risk score accurately predicts ESKD in patients with ANCA-associated vasculitis, with increasing risk associated with higher scores. ANCA kidney risk score performs well in this population, identifying new risk factors and showing similar effectiveness to the previous ANCA renal risk score.

Background: Predicting the outcome of ANCA-associated vasculitis is a difficult task.

Low levels of complement factor C3 at diagnosis can predict outcome in antineutrophil antibody associated vasculitis.

Introduction: Experimental data support the involvement of complement in the pathogenesis of antineutrophil antibody associated vasculitis, and clinical studies describe a more severe disease phenotype in patients with antineutrophil antibody associated vasculitis and complement activation. In the present study, we looked for an association between circulating serum complement factor 3 levels at diagnosis and outcomes.

Methods: One hundred sixty-four patients with antineutrophil antibody associated vasculitis who underwent kidney biopsy at our center during the last 15 years were retrospectively reviewed.

Monitoring disease activity in antineutrophil antibody-associated vasculitis.

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) comprises a group of multisystem disorders with alternating periods of relapse and remission. Beyond that, a smouldering progress during apparently clinically silent phases often develops. AAVs are subgrouped in microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA) and renal limited vasculitis (RLV).

Reliability and accuracy of single-molecule FRET studies for characterization of structural dynamics and distances in proteins.

Single-molecule Förster-resonance energy transfer (smFRET) experiments allow the study of biomolecular structure and dynamics in vitro and in vivo. We performed an international blind study involving 19 laboratories to assess the uncertainty of FRET experiments for proteins with respect to the measured FRET efficiency histograms, determination of distances, and the detection and quantification of structural dynamics. Using two protein systems with distinct conformational changes and dynamics, we obtained an uncertainty of the FRET efficiency ≤0.

Publisher Correction: Precision and accuracy of single-molecule FRET measurements-a multi-laboratory benchmark study.

This paper was originally published under standard Springer Nature copyright. As of the date of this correction, the Analysis is available online as an open-access paper with a CC-BY license. No other part of the paper has been changed.

Precision and accuracy of single-molecule FRET measurements-a multi-laboratory benchmark study.

Single-molecule Förster resonance energy transfer (smFRET) is increasingly being used to determine distances, structures, and dynamics of biomolecules in vitro and in vivo. However, generalized protocols and FRET standards to ensure the reproducibility and accuracy of measurements of FRET efficiencies are currently lacking. Here we report the results of a comparative blind study in which 20 labs determined the FRET efficiencies (E) of several dye-labeled DNA duplexes.

Excited-state annihilation reduces power dependence of single-molecule FRET experiments.

Single-molecule Förster resonance energy transfer (FRET) experiments are an important method for probing biomolecular structure and dynamics. The results from such experiments appear to be surprisingly independent of the excitation power used, in contradiction to the simple photophysical mechanism usually invoked for FRET. Here we show that excited-state annihilation processes are an essential cause of this behavior.

The spectroscopic ruler revisited at 77 K.

We report on single-molecule FRET measurements on the classical molecular ruler polyproline immersed in amorphous ice at 77 K. Confocal scanning microscopy allows for observation of the fluorescence of the dyes Alexa Fluor 488 as the donor and Alexa Fluor 594 as the acceptor in the FRET experiment. The dipole orientations are fixed in amorphous ice leading to a broad distribution of transfer efficiencies.

Conformational plasticity and dynamics in the generic protein folding catalyst SlyD unraveled by single-molecule FRET.

The relation between conformational dynamics and chemistry in enzyme catalysis recently has received increasing attention. While, in the past, the mechanochemical coupling was mainly attributed to molecular motors, nowadays, it seems that this linkage is far more general. Single-molecule fluorescence methods are perfectly suited to directly evidence conformational flexibility and dynamics.

From the Cover: Charge interactions can dominate the dimensions of intrinsically disordered proteins.

Many eukaryotic proteins are disordered under physiological conditions, and fold into ordered structures only on binding to their cellular targets. Such intrinsically disordered proteins (IDPs) often contain a large fraction of charged amino acids. Here, we use single-molecule Förster resonance energy transfer to investigate the influence of charged residues on the dimensions of unfolded and intrinsically disordered proteins.