Validation of 3D cryoEM single particle reconstruction correctness and handedness with Ewald's sphere correction.

The correct description of quantum scattering places the observed scattering contributions on the Ewald's sphere and its Friedel mate. In electron microscopy, due to the large radius of the Ewald's sphere, these contributions are typically merged during data analysis. We present an approach that separates and factorizes these contributions into inversion-symmetric and inversion-antisymmetric components.

Solvent organization in the ultrahigh-resolution crystal structure of crambin at room temperature.

Ultrahigh-resolution structures provide unprecedented details about protein dynamics, hydrogen bonding and solvent networks. The reported 0.70 Å, room-temperature crystal structure of crambin is the highest-resolution ambient-temperature structure of a protein achieved to date.

CryoEM single particle reconstruction with a complex-valued particle stack.

Single particle reconstruction (SPR) in cryoEM is an image processing task with an elaborate hierarchy that starts with many very noisy multi-frame images. Efficient representation of the intermediary image structures is critical for keeping the calculations manageable. One such intermediary structure is called a particle stack and contains cut-out images of particles in square boxes of predefined size.

Monomer and dimer structures of cytochrome bo ubiquinol oxidase from Escherichia coli.

The Escherichia coli cytochrome bo ubiquinol oxidase is a four-subunit heme-copper oxidase that serves as a proton pump in the E. coli aerobic respiratory chain. Despite many mechanistic studies, it is unclear whether this ubiquinol oxidase functions as a monomer, or as a dimer in a manner similar to its eukaryotic counterparts-the mitochondrial electron transport complexes.

Molecular analysis and essentiality of Aro1 shikimate biosynthesis multi-enzyme in .

In the human fungal pathogen , encodes an essential multi-enzyme that catalyses consecutive steps in the shikimate pathway for biosynthesis of chorismate, a precursor to folate and the aromatic amino acids. We obtained the first molecular image of Aro1 that reveals the architecture of all five enzymatic domains and their arrangement in the context of the full-length protein. Aro1 forms a flexible dimer allowing relative autonomy of enzymatic function of the individual domains.

Optimal structure determination from sub-optimal diffraction data.

Herein we present the newest version of the HKL-3000 system that integrates data collection, data reduction, phasing, model building, refinement, and validation. The system significantly accelerates the process of structure determination and has proven its high value for the determination of very high-quality structures. The heuristic for choosing the best approach for every step of structure determination for various quality samples and diffraction data has been optimized.

Structural basis for IFN antagonism by human respiratory syncytial virus nonstructural protein 2.

Human respiratory syncytial virus (RSV) nonstructural protein 2 (NS2) inhibits host interferon (IFN) responses stimulated by RSV infection by targeting early steps in the IFN-signaling pathway. But the molecular mechanisms related to how NS2 regulates these processes remain incompletely understood. To address this gap, here we solved the X-ray crystal structure of NS2.

Synchrotron Radiation as a Tool for Macromolecular X-Ray Crystallography: a XXI Century Perspective.

Intense X-rays available at powerful synchrotron beamlines provide macromolecular crystallographers with an incomparable tool for investigating biological phenomena on an atomic scale. The resulting insights into the mechanism's underlying biological processes have played an essential role and shaped biomedical sciences during the last 30 years, considered the "golden age" of structural biology. In this review, we analyze selected aspects of the impact of synchrotron radiation on structural biology.

High-resolution cryo-EM reconstructions in the presence of substantial aberrations.

Here, an analysis is performed of how uncorrected antisymmetric aberrations, such as coma and trefoil, affect cryo-EM single-particle reconstruction (SPR) results, and an analytical formula quantifying information loss owing to their presence is inferred that explains why Fourier-shell coefficient-based statistics may report significantly overestimated resolution if these aberrations are not fully corrected. The analysis is validated with reference-based aberration refinement for two cryo-EM SPR data sets acquired with a 200 kV microscope in the presence of coma exceeding 40 µm, and 2.3 and 2.

Mutation severity spectrum of rare alleles in the human genome is predictive of disease type.

The human genome harbors a variety of genetic variations. Single-nucleotide changes that alter amino acids in protein-coding regions are one of the major causes of human phenotypic variation and diseases. These single-amino acid variations (SAVs) are routinely found in whole genome and exome sequencing.

NMR and crystallographic structural studies of the extremely stable monomeric variant of human cystatin C with single amino acid substitution.

Human cystatin C (hCC), a member of the superfamily of papain-like cysteine protease inhibitors, is the most widespread cystatin in human body fluids. This small protein, in addition to its physiological function, is involved in various diseases, including cerebral amyloid angiopathy, cerebral hemorrhage, stroke, and dementia. Physiologically active hCC is a monomer.

Crystal structure of native α-L-rhamnosidase from Aspergillus terreus.

α-L-Rhamnosidases cleave terminal nonreducing α-L-rhamnosyl residues from many natural rhamnoglycosides. This makes them catalysts of interest for various biotechnological applications. The X-ray structure of the GH78 family α-L-rhamnosidase from Aspergillus terreus has been determined at 1.

The Bear Giant-Skipper genome suggests genetic adaptations to living inside yucca roots.

Giant-Skippers (Megathymini) are unusual thick-bodied, moth-like butterflies whose caterpillars feed inside Yucca roots and Agave leaves. Giant-Skippers are attributed to the subfamily Hesperiinae and they are endemic to southern and mostly desert regions of the North American continent. To shed light on the genotypic determinants of their unusual phenotypic traits, we sequenced and annotated a draft genome of the largest Giant-Skipper species, the Bear (Megathymus ursus violae).

Real-space analysis of radiation-induced specific changes with independent component analysis.

A method of analysis is presented that allows for the separation of specific radiation-induced changes into distinct components in real space. The method relies on independent component analysis (ICA) and can be effectively applied to electron density maps and other types of maps, provided that they can be represented as sets of numbers on a grid. Here, for glucose isomerase crystals, ICA was used in a proof-of-concept analysis to separate temperature-dependent and temperature-independent components of specific radiation-induced changes for data sets acquired from multiple crystals across multiple temperatures.

Crystal structure of native β-N-acetylhexosaminidase isolated from Aspergillus oryzae sheds light onto its substrate specificity, high stability, and regulation by propeptide.

Unlabelled: β-N-acetylhexosaminidase from the fungus Aspergillus oryzae is a secreted extracellular enzyme that cleaves chitobiose into constituent monosaccharides. It belongs to the GH 20 glycoside hydrolase family and consists of two N-glycosylated catalytic cores noncovalently associated with two 10-kDa O-glycosylated propeptides. We used X-ray diffraction and mass spectrometry to determine the structure of A.

Complete Genome of , The First Representative of the Eudaminae Subfamily of Skippers.

Background: The Hoary Edge Skipper (Achalarus lyciades) is an eastern North America endemic butterfly from the Eudaminae subfamily of skippers named for an underside whitish patch near the hindwing edge. Its caterpillars feed on legumes, in contrast to Grass skippers (subfamily Hesperiinae) which feed exclusively on monocots.

Results: To better understand the evolution and phenotypic diversification of Skippers (family Hesperiidae), we sequenced, assembled and annotated a complete genome draft and transcriptome of a wild-caught specimen of A.

The first complete genomes of Metalmarks and the classification of butterfly families.

Sequencing complete genomes of all major phylogenetic groups of organisms opens unprecedented opportunities to study evolution and genetics. We report draft genomes of Calephelis nemesis and Calephelis virginiensis, representatives of the family Riodinidae. They complete the genomic coverage of butterflies at the family level.

When COI barcodes deceive: complete genomes reveal introgression in hairstreaks.

Two species of hairstreak butterflies from the genus are known in the United States: and Analysis of mitochondrial COI barcodes of revealed -like specimens from the eastern US with atypical barcodes that were 2.6% different from either USA species, but similar to Central American species. To address the possibility that the specimens with atypical barcodes represent an undescribed cryptic species, we sequenced complete genomes of 27 specimens of four species: , , and Some of these specimens were collected up to 60 years ago and preserved dry in museum collections, but nonetheless produced genomes as complete as fresh samples.

Complete genome of , a resilient alien, a cabbage pest, and a source of anti-cancer proteins.

The Small Cabbage White ( ) is originally a Eurasian butterfly. Being accidentally introduced into North America, Australia, and New Zealand a century or more ago, it spread throughout the continents and rapidly established as one of the most abundant butterfly species. Although it is a serious pest of cabbage and other mustard family plants with its caterpillars reducing crops to stems, it is also a source of pierisin, a protein unique to the Whites that shows cytotoxicity to cancer cells.

Crystal structure of the cohesin loader Scc2 and insight into cohesinopathy.

The ring-shaped cohesin complex topologically entraps chromosomes and regulates chromosome segregation, transcription, and DNA repair. The cohesin core consists of the structural maintenance of chromosomes 1 and 3 (Smc1-Smc3) heterodimeric ATPase, the kleisin subunit sister chromatid cohesion 1 (Scc1) that links the two ATPase heads, and the Scc1-bound adaptor protein Scc3. The sister chromatid cohesion 2 and 4 (Scc2-Scc4) complex loads cohesin onto chromosomes.

Crystal structures of the human elongation factor eEFSec suggest a non-canonical mechanism for selenocysteine incorporation.

Selenocysteine is the only proteinogenic amino acid encoded by a recoded in-frame UGA codon that does not operate as the canonical opal stop codon. A specialized translation elongation factor, eEFSec in eukaryotes and SelB in prokaryotes, promotes selenocysteine incorporation into selenoproteins by a still poorly understood mechanism. Our structural and biochemical results reveal that four domains of human eEFSec fold into a chalice-like structure that has similar binding affinities for GDP, GTP and other guanine nucleotides.

Phylogeny Reconstruction with Alignment-Free Method That Corrects for Horizontal Gene Transfer.

Advances in sequencing have generated a large number of complete genomes. Traditionally, phylogenetic analysis relies on alignments of orthologs, but defining orthologs and separating them from paralogs is a complex task that may not always be suited to the large datasets of the future. An alternative to traditional, alignment-based approaches are whole-genome, alignment-free methods.

Estimation of Uncertainties in the Global Distance Test (GDT_TS) for CASP Models.

The Critical Assessment of techniques for protein Structure Prediction (or CASP) is a community-wide blind test experiment to reveal the best accomplishments of structure modeling. Assessors have been using the Global Distance Test (GDT_TS) measure to quantify prediction performance since CASP3 in 1998. However, identifying significant score differences between close models is difficult because of the lack of uncertainty estimations for this measure.