ABSTRACT: In this study, precision N-glycan structure characterization of human serum was established at site-specific level by using our recently developed glycan structure interpretation software, StrucGP.
Project description:In this project we developed a new algorithm termed StrucGP, for large-scale interpretation of N-glycan structures on intact glycopeptides from tandem mass spectrometry data. StrucGP is able to reveal the glycan structure heterogeneity for individual glycosites. The StrucGP also has high performance in distinguishing various structure isoforms and identifying new and rare glycan structures from complex samples.
Project description:In this work, we systematically compared O-acetylated sialoglycopeptides (O-AcSGPs) among sera of human, rat, and mouse to reveal differences and diversities of sialic acid types and O-acetylation patterns in different species. We utilized our high-resolution glycoproteomic approaches to identify numerous O-acetylated N-glycans in rat and mouse sera, and described their structures and distributions across different glycoproteins.
Project description:In this study, we applied the recently developed software, StrucGP to large-scale characterize glycoproteins, and IGPs, as well as precise site-specific glycan structures in human spermatozoa. Furthermore, bioinformatical analyses were conducted to systematically describe the potential functions of N-glycosylation in human spermatozoa.
Project description:In this study, we used human THP-1-derived macrophages as an immune cell model, and systematically performed glycoproteomics of three subtypes of macrophages by StrucGP.To study the N‑Glycoproteomic of them, the intact glycopeptides were first enriched and identified using triplicate mass spectrometry (MS)-based glycoproteomic approaches, then StrucGP was used for subsequent analysis. In total three subtypes of macrophages, these intact glycopeptides consist of 253 N-linked glycan structures at 652 unique glycosites from 372 N-glycoproteins, along with their PSM information. A total of 135, 163, and 201 N-glycan structures were identified from M0, M1, and M2 macrophages, respectively.
Project description:N-linked glycoproteins are known to be important for spermatozoa development and gametes fusion. However, little is known about detailed information of these glycoproteins, particularly the glycosylation sites and its corresponding glycan structures in human spermatozoa. In present study, an in house software coupled with LC-MS/MS analysis of intact glycopeptides was employed to establish a large scale of site-specific N-glycoproteome map in human spermatozoa. The results mapped the large-scale N-glycoproteins in human spermatozoa and interpreted the precise glycan structures with the corresponding glycosites. These presented data laid the foundation for the exploration of biological function of glycosylation on human spermatozoa and glycan structure involved male infertility.
Project description:This study is aimed to comprehensively and globally characterize seminal plasma glycoproteins in a site-specific manner with information of N-glycosites and corresponding glycan structures, as well as glycan isomers using mass spectrometry. Furthermore, the function of specific glycan structures is introduced during human reproduction. In addition, site-specific glycoproteins are compared precisely to explored the sub-glycan structure regulation of glycoprotein in human seminal plasma and spermatozoa.
Project description:Spike (S) protein plays a key role in COVID-19 (SARS-CoV-2) infection and host-cell entry. Previous studies have systematically analyzed site-specific glycans compositions of S protein. Here, we further provide structure-clear N-glycosylation of S protein at site-specific level by using our recently developed structure- and site-specific N-glycoproteomics sequencing algorithm StrucGP. In addition to the common N-glycans as detected in previous studies, many uncommon glycosylation structures such as LacdiNAc structures, Lewis structures, Mannose 6-Phosphate (M6P) residues and bisected core structures were unambiguously mapped at a total of 20 glycosites in the S protein trimer and protomer. These data further supports the glycosylation structural-functional investigations of COVID-19 virus Spike.
Project description:O-Acetylation is a common modification of sialic acid, playing a significant role in glycoprotein stability, immune response, and cell development. The lack of efficient methods for direct analysis of O-acetylated sialoglycopeptides (O-AcSGPs) made the majority of identified O-acetylated sialic acids (O-AcSia) till now had no glycosite/glycoprotein information. Herein, we introduced a new workflow for precise interpretation of O-AcSGPs with probability estimation by recognizing the characteristic B and Y ions of O-AcSias.
Project description:Analysis of mucin type O-glycans linked to serine/threonine of glycoproteins is technically challenging, in part, due to a lack of effective enzymatic tools that enable their analysis. Recently, several O-glycan-specific endoproteases that can cleave the protein adjacent to the appended glycan have been described. Despite significant progress in understanding the biochemistry of these en-zymes, known O-glycoproteases have specificity constrains, such as inefficient cleavage of glycoproteins bearing sialylated O-glycans, high selectivity for certain type of glycoproteins or protein sequence bias, that limit their analytical application. In this study, we examined the capabilities of an immunomodulating metalloprotease (IMPa) from Pseudomonas aeruginosa. The peptide substrate sequence selectivity and its impact on IMPa activity was interrogated using an array of synthetic peptides and their glycoforms. We show that IMPa has no specific P1 residue preference and can tolerate most amino acids at the P1 position, except aspartic acid. The enzyme does not cleave between two adjacent O-glycosites, indicating that O-glycosylated serine/threonine is not allowed at position P1. Glycopeptides with as few as two amino acids on either side of an O-glycosite were specifically cleaved by IMPa. Finally, IMPa efficiently cleaved peptides and proteins carrying sialylated and asialylated O-glycans of varying complexity. We present the use of IMPa in a one-step O-glycoproteomics workflow for glycoprofiling of individual purified glycoproteins granulocyte colony-stimulating factor (G-CSF) and receptor-type tyrosine-protein phosphatase C (CD45) without the need for glycopeptide enrichment. In these examples, IMPa enabled identification of O-glycosites and the range of complex O-glycan structures at each site.
Project description:The secondary structure of an RNA molecule plays an integral role in its maturation, regulation, processing, and functionality. However, the global influence of this feature on plant gene expression is still for the most part unclear. Here, we use a high-throughput, sequencing-based, structure-mapping approach in conjunction with transcriptome-wide sequencing of polyA+-selected (RNA-seq), small (smRNA-seq), and ribosome-bound (ribo-seq) RNA populations to investigate the impact of RNA secondary structure on gene expression regulation in Arabidopsis. From this analysis, we find that highly unpaired and paired RNAs are strongly correlated with euchromatic and heterochromatic epigenetic histone modifications, respectively, providing further evidence that secondary structure is necessary for RNA-mediated posttranscriptional regulatory pathways. Additionally, we uncover key structural patterns across protein-coding transcripts that indicate RNA folding demarcates regions of protein translation and likely affects microRNA-mediated regulation of mRNAs in this model plant. We also reveal that RNA folding is significantly anti-correlated with overall transcript abundance, which is likely due to the increased propensity of highly structured mRNAs to be degraded and/or processed into smRNAs. Finally, we find that secondary structure affects mRNA translation, suggesting that this feature regulates plant gene expression at multiple levels. Overall, our findings provide the first global assessment of RNA folding and its significant regulatory effects in a plant transcriptome. Single-stranded RNA sequencing (ssRNA-seq) and ribosome-bound RNA sequencing (ribo-seq) in immature buds. A single replicate of each library.