Kalign 3: multiple sequence alignment of large data sets

Unveiling the structural and functional implications of uncharacterized NSPs and variations in the molecular toolkit across arteriviruses

Despite considerable scrutiny of mammalian arterivirus genomes, their genomic architecture remains incomplete, with several unannotated non-structural proteins (NSPs) and the enigmatic absence of methyltransferase (MTase) domains. Additionally, the host range of arteriviruses has expanded to include seven newly sequenced genomes from non-mammalian hosts, which remain largely unannotated and await detailed comparisons alongside mammalian isolates. Utilizing comparative genomics approaches and comprehensive sequence-structure analysis, we provide enhanced genomic architecture and annotations for arterivirus genomes. We identified the previously unannotated C-terminal domain of NSP3 as a winged helix-turn-helix domain and classified NSP7 as a new small β-barrel domain, both likely involved in interactions with viral RNA. NSP12 is identified as a derived variant of the N7-MTase-like Rossmann fold domain that retains core structural alignment with N7-MTases in Nidovirales but likely lacks enzymatic functionality due to the erosion of catalytic residues, indicating a unique role specific to mammalian arteriviruses. In contrast, non-mammalian arteriviruses sporadically retain a 2'-O-MTase and an exonuclease (ExoN) domain, which are typically absent in mammalian arteriviruses, highlighting contrasting evolutionary trends and variations in their molecular toolkit. Similar lineage-specific patterns are observed in the diversification of papain-like proteases and structural proteins. Overall, the study extends our knowledge of arterivirus genomic diversity and evolution.

Immunolocalization and 3D modeling of three unique proteins belonging to the costa of Tritrichomonas foetus

Nowadays, even in light of all the massive advances in cell biology, we still find some cellular structures that are not entirely understood. Among those, we highlight the costa, a structure from the mastigont system existent only in some members of the orders Trichomonadida and Tritrichomonadida, including the pathogens of venereal diseases in humans and cattle, Trichomonas vaginalis (T. vaginalis) and Tritrichomonas foetus (T. foetus), respectively. The costa is a prominent striated fiber and, although part of the cytoskeleton, differs from its classical components, and its molecular composition is still not fully characterized. Using proteomics of T. foetus's costa fraction, we previously identified hypothetic proteins, and among these, the protein ARM19800.1 positively localized in the costa and named costain-1. In this study, two other protein candidates were analyzed. To achieve the specific localization of 11810 and 32137 proteins in T. foetus's cells, it was used expansion microscopy and immunocytochemistry. The immunofluorescence revealed the presence of both proteins throughout the whole costa but with different intensities. Immunocytochemistry using negative staining, LR-White, and Epon embedding revealed further analyses of the protein's localization. All techniques confirmed the distinct and distributed localization of both proteins: costain-2 (11810) and costain-3 (32137). Also, AlfaFold3 was used to generate 3D models of the three identified proteins, showing a major prevalence of α-helical spans. Nonetheless, the identification and further characterization of these unique proteins can help understand their functional role in the assembled costa and, therefore, better understand the organization and function of this structure in these organisms.

Impact of Alignments on the Accuracy of Protein Subcellular Localization Predictions

Alignments in bioinformatics refer to the arrangement of sequences to identify regions of similarity that can indicate functional, structural, or evolutionary relationships. They are crucial for bioinformaticians as they enable accurate predictions and analyses in various applications, including protein subcellular localization. The predictive model used in this article is based on a deep - convolutional architecture. We tested configurations of Deep N-to-1 convolutional neural networks of various depths and widths during experimentation for the evaluation of better-performing values across a diverse set of eight classes. For without alignment assessment, sequences are encoded using one-hot encoding, converting each character into a numerical representation, which is straightforward for non-numerical data and useful for machine learning models. For with alignments assessment, multiple sequence alignments (MSAs) are created using PSI-BLAST, capturing evolutionary information by calculating frequencies of residues and gaps. The average difference in peak performance between models with alignments and without alignments is approximately 15.82%. The average difference in the highest accuracy achieved with alignments compared with without alignments is approximately 15.16%. Thus, extensive experimentation indicates that higher alignment accuracy implies a more reliable model and improved prediction accuracy, which can be trusted to deliver consistent performance across different layers and classes of subcellular localization predictions. This research provides valuable insights into prediction accuracies with and without alignments, offering bioinformaticians an effective tool for better understanding while potentially reducing the need for extensive experimental validations. The source code and datasets are available at http://distilldeep.ucd.ie/SCL8/.

Vic9 mycobacteriophage: the first subcluster B2 phage isolated in Russia

Mycobacteriophages are viruses that specifically infect bacteria of the Mycobacterium genus. A substantial collection of mycobacteriophages has been isolated and characterized, offering valuable insights into their diversity and evolution. This collection also holds significant potential for therapeutic applications, particularly as an alternative to antibiotics in combating drug-resistant bacterial strains. In this study, we report the isolation and characterization of a new mycobacteriophage, Vic9, using Mycobacterium smegmatis mc (2)155 as the host strain. Vic9 has been classified within the B2 subcluster of the B cluster. Morphological analysis revealed that Vic9 has a structure typical of siphophages from this subcluster and forms characteristic plaques. The phage adsorbs onto host strain cells within 30 min, and according to one-step growth experiments, its latent period lasts about 90 min, followed by a growth period of 150 min, with an average yield of approximately 68 phage particles per infected cell. In host range experiments, Vic9 efficiently lysed the host strain and also exhibited the ability to lyse M. tuberculosis H37Rv, albeit with a low efficiency of plating (EOP ≈ 2 × 10-5), a typical feature of B2 phages. No lysis was observed in other tested mycobacterial species. The genome of Vic9 comprises 67,543 bp of double-stranded DNA and encodes 89 open reading frames. Our analysis revealed unique features in Vic9, despite its close relationship to other B2 subcluster phages, highlighting its distinct characteristics even among closely related phages. Particularly noteworthy was the discovery of a distinct 435 bp sequence within the gene cluster responsible for queuosine biosynthesis, as well as a recombination event within the structural cassette region (Vic_0033-Vic_0035) among members of the B1, B2, and B3 subclusters. These genetic features are of interest for further research, as they may reveal new mechanisms of phage-bacteria interactions and their potential for developing novel phage therapy methods.

Centromere Landscapes Resolved from Hundreds of Human Genomes

High-fidelity (HiFi) sequencing has facilitated the assembly and analysis of the most repetitive region of the genome, the centromere. Nevertheless, our current understanding of human centromeres is based on a relatively small number of telomere-to-telomere assemblies, which have not yet captured its full diversity. In this study, we investigated the genomic diversity of human centromere higher order repeats (HORs) via both HiFi reads and haplotype-resolved assemblies from hundreds of samples drawn from ongoing pangenome-sequencing projects and reprocessed them via a novel HOR annotation pipeline, HiCAT-human. We used this wealth of data to provide a global survey of the centromeric HOR landscape; in particular, we found that 23 HORs presented significant copy number variability between populations. We detected three centromere genotypes with unbalanced population frequencies on chromosomes 5, 8, and 17. An inter-assembly comparison of HOR loci further revealed that while HOR array structures are diverse, they nevertheless tend to form a number of specific landscapes, each exhibiting different levels of HOR subunit expansion and possibly reflecting a cyclical evolutionary transition from homogeneous to nested structures and back.

Diversity of Gibberellin 2-oxidase genes in the barley genome offers opportunities for genetic improvement

INTRODUCTION

Gibberellin (GA) is a vital phytohormone in regulating plant growth and development. During the "Green Revolution", modification of GA-related genes created semi-dwarfing phenotype in cereal crops but adversely affected grain weight. Gibberellin 2-oxidases (GA2oxs) in barley act as key catabolic enzymes in deactivating GA, but their functions are still less known.

OBJECTIVES

This study investigates the physiological function of two HvGA2ox genes in barley and identifies novel semi-dwarf alleles with minimum impacts on other agronomic traits.

METHODS

Virus-induced gene silencing and CRISPR/Cas9 technology were used to manipulate gene expression of HvGA2ox9 and HvGA2ox8a in barley and RNA-seq was conducted to compare the transcriptome between wild type and mutants. Also, field trials in multiple environments were performed to detect the functional haplotypes.

RESULTS

There were ten GA2oxs that distinctly expressed in shoot, tiller, inflorescence, grain, embryo and root. Knockdown of HvGA2ox9 did not affect plant height, while ga2ox8a mutants generated by CRISPR/Cas9 increased plant height and significantly altered seed width and weight due to the increased bioactive GA4 level. RNA-seq analysis revealed that genes involved in starch and sucrose metabolism were significantly decreased in the inflorescence of ga2ox8a mutants. Furthermore, haplotype analysis revealed one naturally occurring HvGA2ox8a haplotype was associated with decreased plant height, early flowering and wider and heavier seed.

CONCLUSION

Our results demonstrate the potential of manipulating GA2ox genes to fine tune GA signalling and biofunctions in desired plant tissues and open a promising avenue for minimising the trade-off effects of Green Revolution semi-dwarfing genes on grain size and weight. The knowledge will promote the development of next generation barley cultivars with better adaptation to a changing climate.

ReAlign-N: an integrated realignment approach for multiple nucleic acid sequence alignment, combining global and local realignments

Ensuring accurate multiple sequence alignment (MSA) is essential for comprehensive biological sequence analysis. However, the complexity of evolutionary relationships often results in variations that generic alignment tools may not adequately address. Realignment is crucial to remedy this issue. Currently, there is a lack of realignment methods tailored for nucleic acid sequences, particularly for lengthy sequences. Thus, there's an urgent need for the development of realignment methods better suited to address these challenges. This study presents ReAlign-N, a realignment method explicitly designed for multiple nucleic acid sequence alignment. ReAlign-N integrates both global and local realignment strategies for improved accuracy. In the global realignment phase, ReAlign-N incorporates K-Band and innovative memory-saving technology into the dynamic programming approach, ensuring high efficiency and minimal memory requirements for large-scale realignment tasks. The local realignment stage employs full matching and entropy scoring methods to identify low-quality regions and conducts realignment through MAFFT. Experimental results demonstrate that ReAlign-N consistently outperforms initial alignments on simulated and real datasets. Furthermore, compared to ReformAlign, the only existing multiple nucleic acid sequence realignment tool, ReAlign-N, exhibits shorter running times and occupies less memory space. The source code and test data for ReAlign-N are available on GitHub (https://github.com/malabz/ReAlign-N).

Steering veridical large language model analyses by correcting and enriching generated database queries: first steps toward ChatGPT bioinformatics

Large language models (LLMs) leverage factual knowledge from pretraining. Yet this knowledge remains incomplete and sometimes challenging to retrieve-especially in scientific domains not extensively covered in pretraining datasets and where information is still evolving. Here, we focus on genomics and bioinformatics. We confirm and expand upon issues with plain ChatGPT functioning as a bioinformatics assistant. Poor data retrieval and hallucination lead ChatGPT to err, as do incorrect sequence manipulations. To address this, we propose a system basing LLM outputs on up-to-date, authoritative facts and facilitating LLM-guided data analysis. Specifically, we introduce NagGPT, a middleware tool to insert between LLMs and databases, designed to bridge gaps in LLM knowledge and usage of database application programming interfaces. NagGPT proxies LLM-generated database queries, with special handling of incorrect queries. It acts as a gatekeeper between query responses and the LLM prompt, redirecting large responses to files but providing a synthesized snippet and injecting comments to steer the LLM. A companion OpenAI custom GPT, Genomics Fetcher-Analyzer, connects ChatGPT with NagGPT. It steers ChatGPT to generate and run Python code, performing bioinformatics tasks on data dynamically retrieved from a dozen common genomics databases (e.g. NCBI, Ensembl, UniProt, WormBase, and FlyBase). We implement partial mitigations for encountered challenges: detrimental interactions between code generation style and data analysis, confusion between database identifiers, and hallucination of both data and actions taken. Our results identify avenues to augment ChatGPT as a bioinformatics assistant and, more broadly, to improve factual accuracy and instruction following of unmodified LLMs.

Full-resolution HLA and KIR gene annotations for human genome assemblies

The human leukocyte antigen (HLA) genes and the killer cell immunoglobulin-like receptor (KIR) genes are critical to immune responses and are associated with many immune-related diseases. Located in highly polymorphic regions, it is difficult to study them with traditional short-read alignment-based methods. Although modern long-read assemblers can often assemble these genes, using existing tools to annotate HLA and KIR genes in these assemblies remains a nontrivial task. Here, we describe Immuannot, a new computation tool to annotate the gene structures of HLA and KIR genes and to type the allele of each gene. Applying Immuannot to 56 regional and 212 whole-genome assemblies from previous studies, we annotate 9931 HLA and KIR genes and found that almost half of these genes, 4068, have novel sequences compared with the current Immuno Polymorphism Database (IPD). These novel gene sequences are represented by 2664 distinct alleles, some of which contained nonsynonymous variations, resulting in 92 novel protein sequences. We demonstrate the complex haplotype structures at the two loci and report the linkage between HLA/KIR haplotypes and gene alleles. We anticipate that Immuannot will speed up the discovery of new HLA/KIR alleles and enable the association of HLA/KIR haplotype structures with clinical outcomes in the future.

Niche-Aware Metagenomic Screening for Enzyme Methioninase Illuminates Its Contribution to Metabolic Syntrophy

The single-step methioninase-mediated degradation of methionine (as a sulfur containing amino acid) is a reaction at the interface of carbon, nitrogen, sulfur, and methane metabolism in microbes. This enzyme also has therapeutic application due to its role in starving auxotrophic cancer cells. Applying our refined in silico screening pipeline on 33,469 publicly available genome assemblies and 1878 metagenome assembled genomes/single-cell amplified genomes from brackish waters of the Caspian Sea and the Fennoscandian Shield deep groundwater resulted in recovering 1845 methioninases. The majority of recovered methioninases belong to representatives of phyla Proteobacteria (50%), Firmicutes (29%), and Firmicutes_A (13%). Prevalence of methioninase among anaerobic microbes and in the anoxic deep groundwater together with the relevance of its products for energy conservation in anaerobic metabolism highlights such environments as desirable targets for screening novel methioninases and resolving its contribution to microbial metabolism and interactions. Among archaea, majority of detected methioninases are from representatives of Methanosarcina that are able to use methanethiol, the sulfur containing product from methionine degradation, as a precursor for methanogenesis. Branching just outside these archaeal methioninases in the phylogenetic tree, we recovered three methioninases belonging to representatives of Patescibacteria reconstructed from deep groundwater metagenomes. We hypothesize that methioninase in Patescibacteria could contribute to their syntrophic interactions where their methanogenic partners/hosts benefit from the produced 2-oxobutyrate and methanethiol. Our results underscore the significance of accounting for specific ecological niche in screening for enzyme variates with desired characteristics. Finally, complementing of our findings with experimental validation of methioninase activity confirms the potential of our in silico screening in clarifying the peculiar ecological role of methioninase in anoxic environments.

Structural basis of MICAL autoinhibition

MICAL proteins play a crucial role in cellular dynamics by binding and disassembling actin filaments, impacting processes like axon guidance, cytokinesis, and cell morphology. Their cellular activity is tightly controlled, as dysregulation can lead to detrimental effects on cellular morphology. Although previous studies have suggested that MICALs are autoinhibited, and require Rab proteins to become active, the detailed molecular mechanisms remained unclear. Here, we report the cryo-EM structure of human MICAL1 at a nominal resolution of 3.1 Å. Structural analyses, alongside biochemical and functional studies, show that MICAL1 autoinhibition is mediated by an intramolecular interaction between its N-terminal catalytic and C-terminal coiled-coil domains, blocking F-actin interaction. Moreover, we demonstrate that allosteric changes in the coiled-coil domain and the binding of the tripartite assembly of CH-L2α1-LIM domains to the coiled-coil domain are crucial for MICAL activation and autoinhibition. These mechanisms appear to be evolutionarily conserved, suggesting a potential universality across the MICAL family.

Recurrent evolution and selection shape structural diversity at the amylase locus

The adoption of agriculture triggered a rapid shift towards starch-rich diets in human populations1. Amylase genes facilitate starch digestion, and increased amylase copy number has been observed in some modern human populations with high-starch intake2, although evidence of recent selection is lacking3,4. Here, using 94 long-read haplotype-resolved assemblies and short-read data from approximately 5,600 contemporary and ancient humans, we resolve the diversity and evolutionary history of structural variation at the amylase locus. We find that amylase genes have higher copy numbers in agricultural populations than in fishing, hunting and pastoral populations. We identify 28 distinct amylase structural architectures and demonstrate that nearly identical structures have arisen recurrently on different haplotype backgrounds throughout recent human history. AMY1 and AMY2A genes each underwent multiple duplication/deletion events with mutation rates up to more than 10,000-fold the single-nucleotide polymorphism mutation rate, whereas AMY2B gene duplications share a single origin. Using a pangenome-based approach, we infer structural haplotypes across thousands of humans identifying extensively duplicated haplotypes at higher frequency in modern agricultural populations. Leveraging 533 ancient human genomes, we find that duplication-containing haplotypes (with more gene copies than the ancestral haplotype) have rapidly increased in frequency over the past 12,000 years in West Eurasians, suggestive of positive selection. Together, our study highlights the potential effects of the agricultural revolution on human genomes and the importance of structural variation in human adaptation.

Rational enzyme design by reducing the number of hotspots and library size

Biocatalysts that are eco-friendly, sustainable, and highly specific have great potential for applications in the production of fine chemicals, food, detergents, biofuels, pharmaceuticals, and more. However, due to factors such as low activity, narrow substrate scope, poor thermostability, or incorrect selectivity, most natural enzymes cannot be directly used for large-scale production of the desired products. To overcome these obstacles, protein engineering methods have been developed over decades and have become powerful and versatile tools for adapting enzymes with improved catalytic properties or new functions. The vastness of the protein sequence space makes screening a bottleneck in obtaining advantageous mutated enzymes in traditional directed evolution. In the realm of mathematics, there are two major constraints in the protein sequence space: (1) the number of residue substitutions (M); and (2) the number of codons encoding amino acids as building blocks (N). This feature review highlights protein engineering strategies to reduce screening efforts from two dimensions by reducing the numbers M and N, and also discusses representative seminal studies of rationally engineered natural enzymes to deliver new catalytic functions.

An entropy-based study on the mutational landscape of SARS-CoV-2 in USA: Comparing different variants and revealing co-mutational behavior of proteins

COVID-19 emergency has pushed the international scientific community to use every resource to combat the spread of the virus, to understand its biology and predict its possible evolution in terms of new variants. Since the first SARS-CoV-2 virus nucleotide and amino acid sequences were made available, information theory was used to study how viral information content was changing over time and then trace the evolution of its mutational landscape. In this work we analyzed SARS-CoV-2 sequences collected mainly in the USA in a period from March 2020 until December 2022 and computed mutation profiles of viral proteins over time through an entropy-based approach using Shannon Entropy and Hellinger distance. This representation allows an at-a-glance view of the mutational landscape of viral proteins over time and can provide new insights on the evolution of the virus from different points of view. Non-structural proteins typically showed flat mutation profiles, characterized by a very low Average mutation Entropy, while accessory and structural proteins showed mostly non uniform and high mutation profiles, often coupled with the predominance of variants. Interestingly NSP2 protein, whose function is currently still debated, falls in the same branch of NSP14 and NSP10 in the phylogenetic tree of mutations constructed through correlations of mutation profiles, suggesting a co-evolution of those proteins and a possible functional link with each other. To the best of our knowledge this is the first study based on a massive amount of data (n = 107,939,973) that analyzes from an entropy point of view the mutational landscape of SARS-CoV-2 over time and depicts a mutational temporal profile of each protein of the virus.

learnMSA2: deep protein multiple alignments with large language and hidden Markov models

MOTIVATION

For the alignment of large numbers of protein sequences, tools are predominant that decide to align two residues using only simple prior knowledge, e.g. amino acid substitution matrices, and using only part of the available data. The accuracy of state-of-the-art programs declines with decreasing sequence identity and when increasingly large numbers of sequences are aligned. Recently, transformer-based deep-learning models started to harness the vast amount of protein sequence data, resulting in powerful pretrained language models with the main purpose of generating high-dimensional numerical representations, embeddings, for individual sites that agglomerate evolutionary, structural, and biophysical information.

RESULTS

We extend the traditional profile hidden Markov model so that it takes as inputs unaligned protein sequences and the corresponding embeddings. We fit the model with gradient descent using our existing differentiable hidden Markov layer. All sequences and their embeddings are jointly aligned to a model of the protein family. We report that our upgraded HMM-based aligner, learnMSA2, combined with the ProtT5-XL protein language model aligns on average almost 6% points more columns correctly than the best amino acid-based competitor and scales well with sequence number. The relative advantage of learnMSA2 over other programs tends to be greater when the sequence identity is lower and when the number of sequences is larger. Our results strengthen the evidence on the rich information contained in protein language models' embeddings and their potential downstream impact on the field of bioinformatics. Availability and implementation:  https://github.com/Gaius-Augustus/learnMSA, PyPI and Bioconda, evaluation: https://github.com/felbecker/snakeMSA.

Identification of mobile genetic elements with geNomad

Identifying and characterizing mobile genetic elements in sequencing data is essential for understanding their diversity, ecology, biotechnological applications and impact on public health. Here we introduce geNomad, a classification and annotation framework that combines information from gene content and a deep neural network to identify sequences of plasmids and viruses. geNomad uses a dataset of more than 200,000 marker protein profiles to provide functional gene annotation and taxonomic assignment of viral genomes. Using a conditional random field model, geNomad also detects proviruses integrated into host genomes with high precision. In benchmarks, geNomad achieved high classification performance for diverse plasmids and viruses (Matthews correlation coefficient of 77.8% and 95.3%, respectively), substantially outperforming other tools. Leveraging geNomad's speed and scalability, we processed over 2.7 trillion base pairs of sequencing data, leading to the discovery of millions of viruses and plasmids that are available through the IMG/VR and IMG/PR databases. geNomad is available at https://portal.nersc.gov/genomad .

Positive residues of the SARS-CoV-2 fusion domain are key contributors to the initiation of membrane fusion

SARS-CoV-2 is one of the most infectious viruses ever recorded. Despite a plethora of research over the last several years, the viral life cycle is still not well understood, particularly membrane fusion. This process is initiated by the fusion domain (FD), a highly conserved stretch of amino acids consisting of a fusion peptide (FP) and fusion loop (FL), which in synergy perturbs the target cells' lipid membrane to lower the energetic cost necessary for fusion. In this study, through a mutagenesis-based approach, we have investigated the basic residues within the FD (K825, K835, R847, K854) utilizing an in vitro fusion assay and 19F NMR, validated by traditional 13C 15N techniques. Alanine and charge-conserving mutants revealed every basic residue plays a highly specific role within the mechanism of initiating fusion. Intriguingly, K825A led to increased fusogenecity which was found to be correlated to the number of amino acids within helix one, further implicating the role of this specific helix within the FD's fusion mechanism. This work has found basic residues to be important within the FDs fusion mechanism and highlights K825A, a specific mutation made within the FD of the SARS-CoV-2 spike protein, as requiring further investigation due to its potential to contribute to a more virulent strain of SARS-CoV-2.

Machine learning-based classification reveals distinct clusters of non-coding genomic allelic variations associated with Erm-mediated antibiotic resistance

The erythromycin resistance RNA methyltransferase (erm) confers cross-resistance to all therapeutically important macrolides, lincosamides, and streptogramins (MLS phenotype). The expression of erm is often induced by the macrolide-mediated ribosome stalling in the upstream co-transcribed leader sequence, thereby triggering a conformational switch of the intergenic RNA hairpins to allow the translational initiation of erm. We investigated the evolutionary emergence of the upstream erm regulatory elements and the impact of allelic variation on erm expression and the MLS phenotype. Through systematic profiling of the upstream regulatory sequences across all known erm operons, we observed that specific erm subfamilies, such as ermB and ermC, have independently evolved distinct configurations of small upstream ORFs and palindromic repeats. A population-wide genomic analysis of the upstream ermB regions revealed substantial non-random allelic variation at numerous positions. Utilizing machine learning-based classification coupled with RNA structure modeling, we found that many alleles cooperatively influence the stability of alternative RNA hairpin structures formed by the palindromic repeats, which, in turn, affects the inducibility of ermB expression and MLS phenotypes. Subsequent experimental validation of 11 randomly selected variants demonstrated an impressive 91% accuracy in predicting MLS phenotypes. Furthermore, we uncovered a mixed distribution of MLS-sensitive and MLS-resistant ermB loci within the evolutionary tree, indicating repeated and independent evolution of MLS resistance. Taken together, this study not only elucidates the evolutionary processes driving the emergence and development of MLS resistance but also highlights the potential of using non-coding genomic allele data to predict antibiotic resistance phenotypes.

IMPORTANCE

Antibiotic resistance (AR) poses a global health threat as the efficacy of available antibiotics has rapidly eroded due to the widespread transmission of AR genes. Using Erm-dependent MLS resistance as a model, this study highlights the significance of non-coding genomic allelic variations. Through a comprehensive analysis of upstream regulatory elements within the erm family, we elucidated the evolutionary emergence and development of AR mechanisms. Leveraging population-wide machine learning (ML)-based genomic analysis, we transformed substantial non-random allelic variations into discernible clusters of elements, enabling precise prediction of MLS phenotypes from non-coding regions. These findings offer deeper insight into AR evolution and demonstrate the potential of harnessing non-coding genomic allele data for accurately predicting AR phenotypes.

The EMBL-EBI Job Dispatcher sequence analysis tools framework in 2024

The EMBL-EBI Job Dispatcher sequence analysis tools framework (https://www.ebi.ac.uk/jdispatcher) enables the scientific community to perform a diverse range of sequence analyses using popular bioinformatics applications. Free access to the tools and required sequence datasets is provided through user-friendly web applications, as well as via RESTful and SOAP-based APIs. These are integrated into popular EMBL-EBI resources such as UniProt, InterPro, ENA and Ensembl Genomes. This paper overviews recent improvements to Job Dispatcher, including its brand new website and documentation, enhanced visualisations, improved job management, and a rising trend of user reliance on the service from low- and middle-income regions.

The phage shock protein (PSP) envelope stress response: discovery of novel partners and evolutionary history

Bacterial phage shock protein (PSP) systems stabilize the bacterial cell membrane and protect against envelope stress. These systems have been associated with virulence, but despite their critical roles, PSP components are not well characterized outside proteobacteria. Using comparative genomics and protein sequence-structure-function analyses, we systematically identified and analyzed PSP homologs, phyletic patterns, domain architectures, and gene neighborhoods. This approach underscored the evolutionary significance of the system, revealing that its core protein PspA (Snf7 in ESCRT outside bacteria) was present in the last universal common ancestor and that this ancestral functionality has since diversified into multiple novel, distinct PSP systems across life. Several novel partners of the PSP system were identified: (i) the Toastrack domain, likely facilitating assembly of sub-membrane stress-sensing and signaling complexes, (ii) the newly defined HTH-associated α-helical signaling domain-PadR-like transcriptional regulator pair system, and (iii) multiple independent associations with ATPase, CesT/Tir-like chaperone, and Band-7 domains in proteins thought to mediate sub-membrane dynamics. Our work also uncovered links between the PSP components and other domains, such as novel variants of SHOCT-like domains, suggesting roles in assembling membrane-associated complexes of proteins with disparate biochemical functions. Results are available at our interactive web app, https://jravilab.org/psp.IMPORTANCEPhage shock proteins (PSP) are virulence-associated, cell membrane stress-protective systems. They have mostly been characterized in Proteobacteria and Firmicutes. We now show that a minimal PSP system was present in the last universal common ancestor that evolved and diversified into newly identified functional contexts. Recognizing the conservation and evolution of PSP systems across bacterial phyla contributes to our understanding of stress response mechanisms in prokaryotes. Moreover, the newly discovered PSP modularity will likely prompt new studies of lineage-specific cell envelope structures, lifestyles, and adaptation mechanisms. Finally, our results validate the use of domain architecture and genetic context for discovery in comparative genomics.

Computational investigation of the inhibitory interaction of IRF3 and SARS-CoV-2 accessory protein ORF3b

ORF3b is one of the SARS-CoV-2 accessory proteins. Previous experimental study suggested that ORF3b prevents IRF3 translocating to nucleus. However, the biophysical mechanism of ORF3b-IRF3 interaction is elusive. Here, we explored the conformation ensemble of ORF3b using all-atom replica exchange molecular dynamics simulation. Disordered ORF3b has mixed α-helix, β-turn and loop conformers. The potential ORF3b-IRF3 binding modes were searched by docking representative ORF3b conformers with IRF3, and 50 ORF3b-IRF3 complex poses were screened using molecular dynamics simulations ranging from 500 to 1000 ns. We found that ORF3b binds IRF3 predominantly on its CBP binding and phosphorylated pLxIS motifs, with CBP binding site has the highest binding affinity. The ORF3b-IRF3 binding residues are highly conserved in SARS-CoV-2. Our results provided biophysics insights into ORF3b-IRF3 interaction and explained its interferon antagonism mechanism.

Global diversity, recurrent evolution, and recent selection on amylase structural haplotypes in humans

The adoption of agriculture, first documented ~12,000 years ago in the Fertile Crescent, triggered a rapid shift toward starch-rich diets in human populations. Amylase genes facilitate starch digestion and increased salivary amylase copy number has been observed in some modern human populations with high starch intake, though evidence of recent selection is lacking. Here, using 52 long-read diploid assemblies and short read data from ~5,600 contemporary and ancient humans, we resolve the diversity, evolutionary history, and selective impact of structural variation at the amylase locus. We find that amylase genes have higher copy numbers in populations with agricultural subsistence compared to fishing, hunting, and pastoral groups. We identify 28 distinct amylase structural architectures and demonstrate that nearly identical structures have arisen recurrently on different haplotype backgrounds throughout recent human history. AMY1 and AMY2A genes each exhibit multiple duplications/deletions with mutation rates >10,000-fold the SNP mutation rate, whereas AMY2B gene duplications share a single origin. Using a pangenome graph-based approach to infer structural haplotypes across thousands of humans, we identify extensively duplicated haplotypes present at higher frequencies in modern day populations with traditionally agricultural diets. Leveraging 533 ancient human genomes we find that duplication-containing haplotypes (i.e. haplotypes with more amylase gene copies than the ancestral haplotype) have increased in frequency more than seven-fold over the last 12,000 years providing evidence for recent selection in West Eurasians. Together, our study highlights the potential impacts of the agricultural revolution on human genomes and the importance of long-read sequencing in identifying signatures of selection at structurally complex loci.

Arrayed in vivo barcoding for multiplexed sequence verification of plasmid DNA and demultiplexing of pooled libraries

Sequence verification of plasmid DNA is critical for many cloning and molecular biology workflows. To leverage high-throughput sequencing, several methods have been developed that add a unique DNA barcode to individual samples prior to pooling and sequencing. However, these methods require an individual plasmid extraction and/or in vitro barcoding reaction for each sample processed, limiting throughput and adding cost. Here, we develop an arrayed in vivo plasmid barcoding platform that enables pooled plasmid extraction and library preparation for Oxford Nanopore sequencing. This method has a high accuracy and recovery rate, and greatly increases throughput and reduces cost relative to other plasmid barcoding methods or Sanger sequencing. We use in vivo barcoding to sequence verify >45 000 plasmids and show that the method can be used to transform error-containing dispersed plasmid pools into sequence-perfect arrays or well-balanced pools. In vivo barcoding does not require any specialized equipment beyond a low-overhead Oxford Nanopore sequencer, enabling most labs to flexibly process hundreds to thousands of plasmids in parallel.

Streptomyces umbrella toxin particles block hyphal growth of competing species

Streptomyces are a genus of ubiquitous soil bacteria from which the majority of clinically utilized antibiotics derive1. The production of these antibacterial molecules reflects the relentless competition Streptomyces engage in with other bacteria, including other Streptomyces species1,2. Here we show that in addition to small-molecule antibiotics, Streptomyces produce and secrete antibacterial protein complexes that feature a large, degenerate repeat-containing polymorphic toxin protein. A cryo-electron microscopy structure of these particles reveals an extended stalk topped by a ringed crown comprising the toxin repeats scaffolding five lectin-tipped spokes, which led us to name them umbrella particles. Streptomyces coelicolor encodes three umbrella particles with distinct toxin and lectin composition. Notably, supernatant containing these toxins specifically and potently inhibits the growth of select Streptomyces species from among a diverse collection of bacteria screened. For one target, Streptomyces griseus, inhibition relies on a single toxin and that intoxication manifests as rapid cessation of vegetative hyphal growth. Our data show that Streptomyces umbrella particles mediate competition among vegetative mycelia of related species, a function distinct from small-molecule antibiotics, which are produced at the onset of reproductive growth and act broadly3,4. Sequence analyses suggest that this role of umbrella particles extends beyond Streptomyces, as we identified umbrella loci in nearly 1,000 species across Actinobacteria.

Application of Computational Techniques in Antibody Fc-Fused Molecule Design for Therapeutics

Since the advent of hybridoma technology in the year 1975, it took a decade to witness the first approved monoclonal antibody Orthoclone OKT39 (muromonab-CD3) in the year 1986. Since then, continuous strides have been made to engineer antibodies for specific desired effects. The engineering efforts were not confined to only the variable domains of the antibody but also included the fragment crystallizable (Fc) region that influences the immune response and serum half-life. Engineering of the Fc fragment would have a profound effect on the therapeutic dose, antibody-dependent cell-mediated cytotoxicity as well as antibody-dependent cellular phagocytosis. The integration of computational techniques into antibody engineering designs has allowed for the generation of testable hypotheses and guided the rational antibody design framework prior to further experimental evaluations. In this article, we discuss the recent works in the Fc-fused molecule design that involves computational techniques. We also summarize the usefulness of in silico techniques to aid Fc-fused molecule design and analysis for the therapeutics application.

TPMA: A two pointers meta-alignment tool to ensemble different multiple nucleic acid sequence alignments

Accurate multiple sequence alignment (MSA) is imperative for the comprehensive analysis of biological sequences. However, a notable challenge arises as no single MSA tool consistently outperforms its counterparts across diverse datasets. Users often have to try multiple MSA tools to achieve optimal alignment results, which can be time-consuming and memory-intensive. While the overall accuracy of certain MSA results may be lower, there could be local regions with the highest alignment scores, prompting researchers to seek a tool capable of merging these locally optimal results from multiple initial alignments into a globally optimal alignment. In this study, we introduce Two Pointers Meta-Alignment (TPMA), a novel tool designed for the integration of nucleic acid sequence alignments. TPMA employs two pointers to partition the initial alignments into blocks containing identical sequence fragments. It selects blocks with the high sum of pairs (SP) scores to concatenate them into an alignment with an overall SP score superior to that of the initial alignments. Through tests on simulated and real datasets, the experimental results consistently demonstrate that TPMA outperforms M-Coffee in terms of aSP, Q, and total column (TC) scores across most datasets. Even in cases where TPMA's scores are comparable to M-Coffee, TPMA exhibits significantly lower running time and memory consumption. Furthermore, we comprehensively assessed all the MSA tools used in the experiments, considering accuracy, time, and memory consumption. We propose accurate and fast combination strategies for small and large datasets, which streamline the user tool selection process and facilitate large-scale dataset integration. The dataset and source code of TPMA are available on GitHub (https://github.com/malabz/TPMA).

Transmission and dynamics of mother-infant gut viruses during pregnancy and early life

Early development of the gut ecosystem is crucial for lifelong health. While infant gut bacterial communities have been studied extensively, the infant gut virome remains under-explored. To study the development of the infant gut virome over time and the factors that shape it, we longitudinally assess the composition of gut viruses and their bacterial hosts in 30 women during and after pregnancy and in their 32 infants during their first year of life. Using shotgun metagenomic sequencing applied to dsDNA extracted from Virus-Like Particles (VLPs) and bacteria, we generate 205 VLP metaviromes and 322 total metagenomes. With this data, we show that while the maternal gut virome composition remains stable during late pregnancy and after birth, the infant gut virome is dynamic in the first year of life. Notably, infant gut viromes contain a higher abundance of active temperate phages compared to maternal gut viromes, which decreases over the first year of life. Moreover, we show that the feeding mode and place of delivery influence the gut virome composition of infants. Lastly, we provide evidence of co-transmission of viral and bacterial strains from mothers to infants, demonstrating that infants acquire some of their virome from their mother's gut.

A cryptic plasmid is among the most numerous genetic elements in the human gut

Plasmids are extrachromosomal genetic elements that often encode fitness-enhancing features. However, many bacteria carry "cryptic" plasmids that do not confer clear beneficial functions. We identified one such cryptic plasmid, pBI143, which is ubiquitous across industrialized gut microbiomes and is 14 times as numerous as crAssphage, currently established as the most abundant extrachromosomal genetic element in the human gut. The majority of mutations in pBI143 accumulate in specific positions across thousands of metagenomes, indicating strong purifying selection. pBI143 is monoclonal in most individuals, likely due to the priority effect of the version first acquired, often from one's mother. pBI143 can transfer between Bacteroidales, and although it does not appear to impact bacterial host fitness in vivo, it can transiently acquire additional genetic content. We identified important practical applications of pBI143, including its use in identifying human fecal contamination and its potential as an alternative approach to track human colonic inflammatory states.

Structural and biophysical analysis of a Haemophilus influenzae tripartite ATP-independent periplasmic (TRAP) transporter

Tripartite ATP-independent periplasmic (TRAP) transporters are secondary-active transporters that receive their substrates via a soluble-binding protein to move bioorganic acids across bacterial or archaeal cell membranes. Recent cryo-electron microscopy (cryo-EM) structures of TRAP transporters provide a broad framework to understand how they work, but the mechanistic details of transport are not yet defined. Here we report the cryo-EM structure of the Haemophilus influenzae N-acetylneuraminate TRAP transporter (HiSiaQM) at 2.99 Å resolution (extending to 2.2 Å at the core), revealing new features. The improved resolution (the previous HiSiaQM structure is 4.7 Å resolution) permits accurate assignment of two Na+ sites and the architecture of the substrate-binding site, consistent with mutagenic and functional data. Moreover, rather than a monomer, the HiSiaQM structure is a homodimer. We observe lipids at the dimer interface, as well as a lipid trapped within the fusion that links the SiaQ and SiaM subunits. We show that the affinity (KD) for the complex between the soluble HiSiaP protein and HiSiaQM is in the micromolar range and that a related SiaP can bind HiSiaQM. This work provides key data that enhances our understanding of the 'elevator-with-an-operator' mechanism of TRAP transporters.

Cell layer-specific expression of the homeotic MADS-box transcription factor PhDEF contributes to modular petal morphogenesis in petunia

Floral homeotic MADS-box transcription factors ensure the correct morphogenesis of floral organs, which are organized in different cell layers deriving from distinct meristematic layers. How cells from these distinct layers acquire their respective identities and coordinate their growth to ensure normal floral organ morphogenesis is unresolved. Here, we studied petunia (Petunia × hybrida) petals that form a limb and tube through congenital fusion. We identified petunia mutants (periclinal chimeras) expressing the B-class MADS-box gene DEFICIENS in the petal epidermis or in the petal mesophyll, called wico and star, respectively. Strikingly, wico flowers form a strongly reduced tube while their limbs are almost normal, while star flowers form a normal tube but greatly reduced and unpigmented limbs, showing that petunia petal morphogenesis is highly modular. These mutants highlight the layer-specific roles of PhDEF during petal development. We explored the link between PhDEF and petal pigmentation, a well-characterized limb epidermal trait. The anthocyanin biosynthesis pathway was strongly downregulated in star petals, including its major regulator ANTHOCYANIN2 (AN2). We established that PhDEF directly binds to the AN2 terminator in vitro and in vivo, suggesting that PhDEF might regulate AN2 expression and therefore petal epidermis pigmentation. Altogether, we show that cell layer-specific homeotic activity in petunia petals differently impacts tube and limb development, revealing the relative importance of the different cell layers in the modular architecture of petunia petals.

Relationships of Late Pleistocene giant deer as revealed by Sinomegaceros mitogenomes from East Asia

The giant deer, widespread in northern Eurasia during the Late Pleistocene, have been classified as western Megaloceros and eastern Sinomegaceros through morphological studies. While Megaloceros's evolutionary history has been unveiled through mitogenomes, Sinomegaceros remains molecularly unexplored. Herein, we generated mitogenomes of giant deer from East Asia. We find that, in contrast to the morphological differences between Megaloceros and Sinomegaceros, they are mixed in the mitochondrial phylogeny, and Siberian specimens suggest a range contact or overlap between these two groups. Meanwhile, one deep divergent clade and another surviving until 20.1 thousand years ago (ka) were detected in northeastern China, the latter implying this area as a potential refugium during the Last Glacial Maximum (LGM). Moreover, stable isotope analyses indicate correlations between climate-introduced vegetation changes and giant deer extinction. Our study demonstrates the genetic relationship between eastern and western giant deer and explores the promoters of their extirpation in northern East Asia.

Whole genome structural predictions reveal hidden diversity in putative oxidative enzymes of the lignocellulose-degrading ascomycete Parascedosporium putredinis NO1

IMPORTANCE

An annotated reference genome has revealed P. putredinis NO1 as a useful resource for the identification of new lignocellulose-degrading enzymes for biorefining of woody plant biomass. Utilizing a "structure-omics"-based searching strategy, we identified new potentially lignocellulose-active sequences that would have been missed by traditional sequence searching methods. These new identifications, alongside the discovery of novel enzymatic functions from this underexplored lineage with the recent discovery of a new phenol oxidase that cleaves the main structural β-O-4 linkage in lignin from P. putredinis NO1, highlight the underexplored and poorly represented family Microascaceae as a particularly interesting candidate worthy of further exploration toward the valorization of high value biorenewable products.

Multiple sequence alignment based on deep reinforcement learning with self-attention and positional encoding

MOTIVATION

Multiple sequence alignment (MSA) is one of the hotspots of current research and is commonly used in sequence analysis scenarios. However, there is no lasting solution for MSA because it is a Nondeterministic Polynomially complete problem, and the existing methods still have room to improve the accuracy.

RESULTS

We propose Deep reinforcement learning with Positional encoding and self-Attention for MSA, based on deep reinforcement learning, to enhance the accuracy of the alignment Specifically, inspired by the translation technique in natural language processing, we introduce self-attention and positional encoding to improve accuracy and reliability. Firstly, positional encoding encodes the position of the sequence to prevent the loss of nucleotide position information. Secondly, the self-attention model is used to extract the key features of the sequence. Then input the features into a multi-layer perceptron, which can calculate the insertion position of the gap according to the features. In addition, a novel reinforcement learning environment is designed to convert the classic progressive alignment into progressive column alignment, gradually generating each column's sub-alignment. Finally, merge the sub-alignment into the complete alignment. Extensive experiments based on several datasets validate our method's effectiveness for MSA, outperforming some state-of-the-art methods in terms of the Sum-of-pairs and Column scores.

AVAILABILITY AND IMPLEMENTATION

The process is implemented in Python and available as open-source software from https://github.com/ZhangLab312/DPAMSA.

SARS-CoV-2 fusion peptide sculpting of a membrane with insertion of charged and polar groups

The fusion peptide of SARS-CoV-2 spike is essential for infection. How this charged and hydrophobic domain occupies and affects membranes needs clarification. Its depth in zwitterionic, bilayered micelles at pH 5 (resembling late endosomes) was measured by paramagnetic NMR relaxation enhancements used to bias molecular dynamics simulations. Asp830 inserted deeply, along with Lys825 or Lys835. Protonation of Asp830 appeared to enhance agreement of simulated and NMR-measured depths. While the fusion peptide occupied a leaflet of the DMPC bilayer, the opposite leaflet invaginated with influx of water and choline head groups in around Asp830 and bilayer-inserted polar side chains. NMR-detected hydrogen exchange found corroborating hydration of the backbone of Thr827-Phe833 inserted deeply in bicelles. Pinching of the membrane at the inserted charge and the intramembrane hydration of polar groups agree with theory. Formation of corridors of hydrated, inward-turned head groups was accompanied by flip-flop of head groups. Potential roles of the defects are discussed.

Clinical and genetic screening in a large Iranian family with Marfan syndrome: A case study

Background and Aims

Marfan syndrome (MFS) is an autosomal dominant genetic disorder caused by pathogenic variants of the fibrillin-1-encoding FBN1 gene that commonly affects the cardiovascular, skeletal, and ocular systems. This study aimed to evaluate the clinical features and genetic causes of the MFS phenotype in a large Iranian family.

Methods

Seventeen affected family members were examined clinically by cardiologists and ophthalmologists. The proband, a 48-year-old woman with obvious signs of MFS, her DNA sample subjected to whole-exome sequencing (WES). The candidate variant was validated by bidirectional sequencing of proband and other available family members. In silico analysis and molecular modeling were conducted to determine the pathogenic effects of the candidate variants.

Results

The most frequent cardiac complications are mitral valve prolapse and regurgitation. Ophthalmic examination revealed iridodonesis and ectopic lentis. A heterozygous missense variant (c.2179T>C/p.C727R) in exon 19 of FBN1 gene was identified and found to cosegregate with affected family members. Its pathogenicity has been predicted using several in silico predictive algorithms. Molecular docking analysis indicated that the variant might affect the binding affinity between FBN1 and LTBP1 proteins by impairing disulfide bond formation.

Conclusion

Our report expands the spectrum of the Marfan phenotype by providing details of its clinical manifestations and disease-associated molecular changes. It also highlights the value of WES in genetic diagnosis and contributes to genetic counseling in families with MFS.

The complete sequence of a human Y chromosome

The human Y chromosome has been notoriously difficult to sequence and assemble because of its complex repeat structure that includes long palindromes, tandem repeats and segmental duplications1-3. As a result, more than half of the Y chromosome is missing from the GRCh38 reference sequence and it remains the last human chromosome to be finished4,5. Here, the Telomere-to-Telomere (T2T) consortium presents the complete 62,460,029-base-pair sequence of a human Y chromosome from the HG002 genome (T2T-Y) that corrects multiple errors in GRCh38-Y and adds over 30 million base pairs of sequence to the reference, showing the complete ampliconic structures of gene families TSPY, DAZ and RBMY; 41 additional protein-coding genes, mostly from the TSPY family; and an alternating pattern of human satellite 1 and 3 blocks in the heterochromatic Yq12 region. We have combined T2T-Y with a previous assembly of the CHM13 genome4 and mapped available population variation, clinical variants and functional genomics data to produce a complete and comprehensive reference sequence for all 24 human chromosomes.

Drug resistance and physiological roles of RND multidrug efflux pumps in Salmonella enterica, Escherichia coli and Pseudomonas aeruginosa

Drug efflux pumps transport antimicrobial agents out of bacteria, thereby reducing the intracellular antimicrobial concentration, which is associated with intrinsic and acquired bacterial resistance to these antimicrobials. As genome analysis has advanced, many drug efflux pump genes have been detected in the genomes of bacterial species. In addition to drug resistance, these pumps are involved in various essential physiological functions, such as bacterial adaptation to hostile environments, toxin and metabolite efflux, biofilm formation and quorum sensing. In Gram-negative bacteria, efflux pumps in the resistance–nodulation–division (RND) superfamily play a clinically important role. In this review, we focus on Gram-negative bacteria, including Salmonella enterica , Escherichia coli and Pseudomonas aeruginosa , and discuss the role of RND efflux pumps in drug resistance and physiological functions.

Genetic conservation across SARS-CoV-2 non-structural proteins - Insights into possible targets for treatment of future viral outbreaks

The majority of SARS-CoV-2 therapeutic development work has focussed on targeting the spike protein, viral polymerase and proteases. As the pandemic progressed, many studies reported that these proteins are prone to high levels of mutation and can become drug resistant. Thus, it is necessary to not only target other viral proteins such as the non-structural proteins (NSPs) but to also target the most conserved residues of these proteins. In order to understand the level of conservation among these viruses, in this review, we have focussed on the conservation across RNA viruses, conservation across the coronaviruses and then narrowed our focus to conservation of NSPs across coronaviruses. We have also discussed the various treatment options for SARS-CoV-2 infection. A synergistic melding of bioinformatics, computer-aided drug-design and in vitro/vivo studies can feed into better understanding of the virus and therefore help in the development of small molecule inhibitors against the viral proteins.

New biochemistry in the Rhodanese-phosphatase superfamily: emerging roles in diverse metabolic processes, nucleic acid modifications, and biological conflicts

The protein-tyrosine/dual-specificity phosphatases and rhodanese domains constitute a sprawling superfamily of Rossmannoid domains that use a conserved active site with a cysteine to catalyze a range of phosphate-transfer, thiotransfer, selenotransfer and redox activities. While these enzymes have been extensively studied in the context of protein/lipid head group dephosphorylation and various thiotransfer reactions, their overall diversity and catalytic potential remain poorly understood. Using comparative genomics and sequence/structure analysis, we comprehensively investigate and develop a natural classification for this superfamily. As a result, we identified several novel clades, both those which retain the catalytic cysteine and those where a distinct active site has emerged in the same location (e.g. diphthine synthase-like methylases and RNA 2' OH ribosyl phosphate transferases). We also present evidence that the superfamily has a wider range of catalytic capabilities than previously known, including a set of parallel activities operating on various sugar/sugar alcohol groups in the context of NAD+-derivatives and RNA termini, and potential phosphate transfer activities involving sugars and nucleotides. We show that such activities are particularly expanded in the RapZ-C-DUF488-DUF4326 clade, defined here for the first time. Some enzymes from this clade are predicted to catalyze novel DNA-end processing activities as part of nucleic-acid-modifying systems that are likely to function in biological conflicts between viruses and their hosts.

Roadmap to the study of gene and protein phylogeny and evolution-A practical guide

Developments in sequencing technologies and the sequencing of an ever-increasing number of genomes have revolutionised studies of biodiversity and organismal evolution. This accumulation of data has been paralleled by the creation of numerous public biological databases through which the scientific community can mine the sequences and annotations of genomes, transcriptomes, and proteomes of multiple species. However, to find the appropriate databases and bioinformatic tools for respective inquiries and aims can be challenging. Here, we present a compilation of DNA and protein databases, as well as bioinformatic tools for phylogenetic reconstruction and a wide range of studies on molecular evolution. We provide a protocol for information extraction from biological databases and simple phylogenetic reconstruction using probabilistic and distance methods, facilitating the study of biodiversity and evolution at the molecular level for the broad scientific community.

Gaining Insight into Large Gene Families with the Aid of Bioinformatic Tools

Proteins participating in plant cell morphogenesis are often encoded by large gene families, in some cases comprising paralogs with variable (modular) domain organization, as in the case of the formin (FH2 protein) family of actin nucleators that can have also additional functions. Unravelling the phylogeny of such a complex gene family brings a number of specific challenges but may be crucial for predictions of protein function and for experimental design. Here we present an overview of our "cottage industry" semi-manual bioinformatic approach, based mostly, though not exclusively, on freely available software tools, which we used to obtain insight into the evolutionary history of plant FH2 proteins and some other components of the plant cell morphogenesis apparatus.

Xenopus laevis lack the critical sperm factor PLCζ

Fertilization of eggs from the African clawed frog Xenopus laevis is characterized by an increase in cytosolic calcium, a phenomenon that is also observed in other vertebrates such as mammals and birds. During fertilization in mammals and birds, the transfer of the soluble PLCζ from sperm into the egg is thought to trigger the release of calcium from the endoplasmic reticulum (ER). Injecting sperm extracts into eggs reproduces this effect, reinforcing the hypothesis that a sperm factor is responsible for calcium release and egg activation. Remarkably, this occurs even when sperm extracts from X. laevis are injected into mouse eggs, suggesting that mammals and X. laevis share a sperm factor. However, X. laevis lacks an annotated PLCZ1 gene, which encodes the PLCζ enzyme. In this study, we attempted to determine whether sperm from X. laevis express an unannotated PLCZ1 ortholog. We identified PLCZ1 orthologs in 11 amphibian species, including 5 that had not been previously characterized, but did not find any in either X. laevis or the closely related Xenopus tropicalis. Additionally, we performed RNA sequencing on testes obtained from adult X. laevis males and did not identify potential PLCZ1 orthologs in our dataset or in previously collected ones. These findings suggest that PLCZ1 may have been lost in the Xenopus lineage and raise the question of how fertilization triggers calcium release and egg activation in these species.

A Maverick-like cluster in the genome of a pathogenic, moderately virulent strain of Gallibacterium anatis, ESV200, a transient biofilm producer

Introduction

Gallibacterium anatis causes gallibacteriosis in birds. These bacteria produce biofilms and secrete several fimbrial appendages as tools to cause disease in animals. G. anatis strains contain up to three types of fimbriae. Complete genome sequencing is the strategy currently used to determine variations in the gene content of G. anatis, although today only the completely circularized genome of G. anatis UMN179 is available.

Methods

The appearance of growth of various strains of G. anatis in liquid culture medium was studied. Biofilm production and how the amount of biofilm was affected by DNase, Proteinase K, and Pronase E enzymes were analyzed. Fimbrial gene expression was performed by protein analysis and qRT-PCR. In an avian model, the pathogenesis generated by the strains G. anatis ESV200 and 12656-12 was investigated. Using bioinformatic tools, the complete genome of G. anatis ESV200 was comparatively studied to search for virulence factors that would help explain the pathogenic behavior of this strain.

Results and Discussion

G. anatis ESV200 strain differs from the 12656-12 strain because it produces a biofilm at 20%. G. anatis ESV200 strain express fimbrial genes and produces biofilm but with a different structure than that observed for strain 12656-12. ESV200 and 12656-12 strains are pathogenic for chickens, although the latter is the most virulent. Here, we show that the complete genome of the ESV200 strain is similar to that of the UNM179 strain. However, these strains have evolved with many structural rearrangements; the most striking chromosomal arrangement is a Maverick-like element present in the ESV200 strain.

Targeted long-read sequencing facilitates phased diploid assembly and genotyping of the human T cell receptor alpha, delta, and beta loci

T cell receptors (TCRs) recognize peptide fragments presented by the major histocompatibility complex (MHC) and are critical to T cell-mediated immunity. Recent data have indicated that genetic diversity within TCR-encoding gene regions is underexplored, limiting understanding of the impact of TCR loci polymorphisms on TCR function in disease, even though TCR repertoire signatures (1) are heritable and (2) associate with disease phenotypes. To address this, we developed a targeted long-read sequencing approach to generate highly accurate haplotype resolved assemblies of the TCR beta (TRB) and alpha/delta (TRA/D) loci, facilitating the genotyping of all variant types, including structural variants. We validate our approach using two mother-father-child trios and 5 unrelated donors representing multiple populations. This resulted in improved genotyping accuracy and the discovery of 84 undocumented V, D, J, and C alleles, demonstrating the utility of this framework for improving our understanding of TCR diversity and function in disease.

HELIOS: High-speed sequence alignment in optics

In response to the imperfections of current sequence alignment methods, originated from the inherent serialism within their corresponding electrical systems, a few optical approaches for biological data comparison have been proposed recently. However, due to their low performance, raised from their inefficient coding scheme, this paper presents a novel all-optical high-throughput method for aligning DNA, RNA, and protein sequences, named HELIOS. The HELIOS method employs highly sophisticated operations to locate character matches, single or multiple mutations, and single or multiple indels within various biological sequences. On the other hand, the HELIOS optical architecture exploits high-speed processing and operational parallelism in optics, by adopting wavelength and polarization of optical beams. For evaluation, the functionality and accuracy of the HELIOS method are approved through behavioral and optical simulation studies, while its complexity and performance are estimated through analytical computation. The accuracy evaluations indicate that the HELIOS method achieves a precise pairwise alignment of two sequences, highly similar to those of Smith-Waterman, Needleman-Wunsch, BLAST, MUSCLE, ClustalW, ClustalΩ, T-Coffee, Kalign, and MAFFT. According to our performance evaluations, the HELIOS optical architecture outperforms all alternative electrical and optical algorithms in terms of processing time and memory requirement, relying on its highly sophisticated method and optical architecture. Moreover, the employed compact coding scheme highly escalates the number of input characters, and hence, it offers reduced time and space complexities, compared to the electrical and optical alternatives. It makes the HELIOS method and optical architecture highly applicable for biomedical applications.

Genome-resolved analyses show an extensive diversification in key aerobic hydrocarbon-degrading enzymes across bacteria and archaea

Background

Hydrocarbons (HCs) are organic compounds composed solely of carbon and hydrogen that are mainly accumulated in oil reservoirs. As the introduction of all classes of hydrocarbons including crude oil and oil products into the environment has increased significantly, oil pollution has become a global ecological problem. However, our perception of pathways for biotic degradation of major HCs and key enzymes in these bioconversion processes has mainly been based on cultured microbes and is biased by uneven taxonomic representation. Here we used Annotree to provide a gene-centric view of the aerobic degradation ability of aliphatic and aromatic HCs in 23,446 genomes from 123 bacterial and 14 archaeal phyla. 

Results

Apart from the widespread genetic potential for HC degradation in Proteobacteria, Actinobacteriota, Bacteroidota, and Firmicutes, genomes from an additional 18 bacterial and 3 archaeal phyla also hosted key HC degrading enzymes. Among these, such degradation potential has not been previously reported for representatives in the phyla UBA8248, Tectomicrobia, SAR324, and Eremiobacterota. Genomes containing whole pathways for complete degradation of HCs were only detected in Proteobacteria and Actinobacteriota. Except for several members of Crenarchaeota, Halobacterota, and Nanoarchaeota that have tmoA, ladA, and alkB/M key genes, respectively, representatives of archaeal genomes made a small contribution to HC degradation. None of the screened archaeal genomes coded for complete HC degradation pathways studied here; however, they contribute significantly to peripheral routes of HC degradation with bacteria.

Conclusion

Phylogeny reconstruction showed that the reservoir of key aerobic hydrocarbon-degrading enzymes in Bacteria and Archaea undergoes extensive diversification via gene duplication and horizontal gene transfer. This diversification could potentially enable microbes to rapidly adapt to novel and manufactured HCs that reach the environment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08906-w.

Structural Basis of Stereospecific Vanadium-Dependent Haloperoxidase Family Enzymes in Napyradiomycin Biosynthesis

Vanadium-dependent haloperoxidases (VHPOs) from Streptomyces bacteria differ from their counterparts in fungi, macroalgae, and other bacteria by catalyzing organohalogenating reactions with strict regiochemical and stereochemical control. While this group of enzymes collectively uses hydrogen peroxide to oxidize halides for incorporation into electron-rich organic molecules, the mechanism for the controlled transfer of highly reactive chloronium ions in the biosynthesis of napyradiomycin and merochlorin antibiotics sets the Streptomyces vanadium-dependent chloroperoxidases apart. Here we report high-resolution crystal structures of two homologous VHPO family members associated with napyradiomycin biosynthesis, NapH1 and NapH3, that catalyze distinctive chemical reactions in the construction of meroterpenoid natural products. The structures, combined with site-directed mutagenesis and intact protein mass spectrometry studies, afforded a mechanistic model for the asymmetric alkene and arene chlorination reactions catalyzed by NapH1 and the isomerase activity catalyzed by NapH3. A key lysine residue in NapH1 situated between the coordinated vanadate and the putative substrate binding pocket was shown to be essential for catalysis. This observation suggested the involvement of the ε-NH2, possibly through formation of a transient chloramine, as the chlorinating species much as proposed in structurally distinct flavin-dependent halogenases. Unexpectedly, NapH3 is modified post-translationally by phosphorylation of an active site His (τ-pHis) consistent with its repurposed halogenation-independent, α-hydroxyketone isomerase activity. These structural studies deepen our understanding of the mechanistic underpinnings of VHPO enzymes and their evolution as enantioselective biocatalysts.

DciA Helicase Operators Exhibit Diversity across Bacterial Phyla

A fundamental requirement for life is the replication of an organism's DNA. Studies in Escherichia coli and Bacillus subtilis have set the paradigm for DNA replication in bacteria. During replication initiation in E. coli and B. subtilis, the replicative helicase is loaded onto the DNA at the origin of replication by an ATPase helicase loader. However, most bacteria do not encode homologs to the helicase loaders in E. coli and B. subtilis. Recent work has identified the DciA protein as a predicted helicase operator that may perform a function analogous to the helicase loaders in E. coli and B. subtilis. DciA proteins, which are defined by the presence of a DUF721 domain (termed the DciA domain herein), are conserved in most bacteria but have only been studied in mycobacteria and gammaproteobacteria (Pseudomonas aeruginosa and Vibrio cholerae). Sequences outside the DciA domain in Mycobacterium tuberculosis DciA are essential for protein function but are not conserved in the P. aeruginosa and V. cholerae homologs, raising questions regarding the conservation and evolution of DciA proteins across bacterial phyla. To comprehensively define the DciA protein family, we took a computational evolutionary approach and analyzed the domain architectures and sequence properties of DciA domain-containing proteins across the tree of life. These analyses identified lineage-specific domain architectures among DciA homologs, as well as broadly conserved sequence-structural motifs. The diversity of DciA proteins represents the evolution of helicase operation in bacterial DNA replication and highlights the need for phylum-specific analyses of this fundamental biological process. IMPORTANCE Despite the fundamental importance of DNA replication for life, this process remains understudied in bacteria outside Escherichia coli and Bacillus subtilis. In particular, most bacteria do not encode the helicase-loading proteins that are essential in E. coli and B. subtilis for DNA replication. Instead, most bacteria encode a DciA homolog that likely constitutes the predominant mechanism of helicase operation in bacteria. However, it is still unknown how DciA structure and function compare across diverse phyla that encode DciA proteins. In this study, we performed computational evolutionary analyses to uncover tremendous diversity among DciA homologs. These studies provide a significant advance in our understanding of an essential component of the bacterial DNA replication machinery.

Phage defence by deaminase-mediated depletion of deoxynucleotides in bacteria

Vibrio cholerae biotype El Tor is perpetuating the longest cholera pandemic in recorded history. The genomic islands VSP-1 and VSP-2 distinguish El Tor from previous pandemic V. cholerae strains. Using a co-occurrence analysis of VSP genes in >200,000 bacterial genomes we built gene networks to infer biological functions encoded in these islands. This revealed that dncV, a component of the cyclic-oligonucleotide-based anti-phage signalling system (CBASS) anti-phage defence system, co-occurs with an uncharacterized gene vc0175 that we rename avcD for anti-viral cytodine deaminase. We show that AvcD is a deoxycytidylate deaminase and that its activity is post-translationally inhibited by a non-coding RNA named AvcI. AvcID and bacterial homologues protect bacterial populations against phage invasion by depleting free deoxycytidine nucleotides during infection, thereby decreasing phage replication. Homologues of avcD exist in all three domains of life, and bacterial AvcID defends against phage infection by combining traits of two eukaryotic innate viral immunity proteins, APOBEC and SAMHD1.

Developments in Algorithms for Sequence Alignment: A Review

The continuous development of sequencing technologies has enabled researchers to obtain large amounts of biological sequence data, and this has resulted in increasing demands for software that can perform sequence alignment fast and accurately. A number of algorithms and tools for sequence alignment have been designed to meet the various needs of biologists. Here, the ideas that prevail in the research of sequence alignment and some quality estimation methods for multiple sequence alignment tools are summarized.