Postnovo: Post-Processing De Novo Peptide Sequences
Ontology highlight
ABSTRACT:
INSTRUMENT(S): LTQ Orbitrap Elite
ORGANISM(S): Synechococcus Sp. Wh 7803 (ncbitaxon:32051) Desulfovibrio Vulgaris Str. Hildenborough (ncbitaxon:882) Escherichia Coli K-12 (ncbitaxon:83333) Rhodopseudomonas Palustris Tie-1 (ncbitaxon:395960)
SUBMITTER: 
Jacob Waldbauer
PROVIDER: MSV000082266 | MassIVE | Tue Apr 10 15:59:00 BST 2018
SECONDARY ACCESSION(S): PXD009462
REPOSITORIES: MassIVE
Similar Datasets
Project description:Dependent on concise, pre-defined protein sequence databases, traditional search algorithms perform poorly when analyzing mass spectra derived from wholly uncharacterized protein products. Conversely, de novo peptide sequencing algorithms can interpret mass spectra without relying on reference databases. However, such algorithms have been difficult to apply to complex protein mixtures, in part due to a lack of methods for automatically validating de novo sequencing results. Here, we present novel metrics for benchmarking de novo sequencing algorithm performance on large scale proteomics datasets, and present a method for accurately calibrating false discovery rates on de novo results. We also present a novel algorithm (LADS) which leverages experimentally disambiguated fragmentation spectra to boost sequencing accuracy and sensitivity. LADS improves sequencing accuracy on longer peptides relative to other algorithms and improves discriminability of correct and incorrect sequences. Using these advancements, we demonstrate accurate de novo identification of peptide sequences not identifiable using database search-based approaches.
2016-01-12 | PXD003317 | Pride
Project description:In maize (Zea mays), irradiation can produce many variants with varying centromeric DNA sequences. We found de novo centromeres in F3-152 and F3-600, which has no canonical centromeric repeat sequences. This centromere is derived from a 1520-kb and 188-kb region on the arm of chromosome 10 and 3. Our results suggest that de novo centromere formation is more common than previously thought and can persist on chromosomal fragments without a canonical centromere providing implications for karyotype evolution.
2019-12-21 | GSE124242 | GEO
Project description:De novo peptide sequencing is a fundamental research area in mass spectrometry (MS) based proteomics. However, those methods have often been evaluated using a couple of simple metrics that do not fully reflect their overall performance. Moreover, there has not been an established method to estimate the false discovery rate (FDR) and the significance of de novo peptide-spectrum matches (PSMs). Here we propose NovoBoard, a comprehensive framework to evaluate the performance of de novo peptide sequencing methods. The framework consists of diverse benchmark datasets (including tryptic, nontryptic, immunopeptidomics, and different species), and a standard set of accuracy metrics to evaluate the fragment ions, amino acids, and peptides of the de novo results. More importantly, a new approach is designed to evaluate de novo peptide sequencing methods on target-decoy spectra and to estimate their FDRs. Our results thoroughly reveal the strengths and weaknesses of different de novo peptide sequencing methods, and how their performances depend on specific applications and the types of data. Our FDR estimation also shows that some tools may perform better than the others in distinguishing between de novo PSMs and random matches, and can be used to assess the significance of de novo PSMs.
2024-08-28 | PXD055277 | Pride
Project description:The ability of centromeres to alternate between active and inactive states indicates significant epigenetic elements controlling centromere assembly and centromere function. In maize (Zea mays), misdivision of the B chromosome centromere on a translocation with the short arm of chromosome 9 (TB-9Sb) can produce many variants with varying centromere sizes and centromeric DNA sequences. In derivatives of TB-9Sb, we found a de novo centromere on chromosome telo-3-3, which has no canonical centromeric repeat sequences. This centromere is derived from a 288-kb region on the short arm of chromosome 9, and is 19 megabases (Mb) removed from the translocation breakpoint of chromosome 9 in TB-9Sb. This centromere is much smaller than normal ones but can be maintained through meiosis. The functional B centromere in progenitor telo2-2 is deleted from telo3-3 but some B-repeat sequences remain. The de novo centromere of telo3-3 becomes inactive in three further derivatives with new centromeres being formed elsewhere on the chromosomes. One such de novo centromere contains only 200-kb CENH3 binding domain. This 200-kb centromere is located 3 Mb removed from the translocation breakpoint in a new location. The deleted B centromere in telo3-3 is activated in two derivatives. Our results suggest that de novo centromere formation is more common than previously thought and can persist on chromosomal fragments without a canonical centromere providing implications for karyotype evolution. ChIP-seq was carried out with anti-CENH3 antibodies using material from young leaves with control, telo3-3 and its derivate.
2015-03-03 | E-GEOD-59124 | biostudies-arrayexpress
Project description:The ability of centromeres to alternate between active and inactive states indicates significant epigenetic elements controlling centromere assembly and centromere function. In maize (Zea mays), misdivision of the B chromosome centromere on a translocation with the short arm of chromosome 9 (TB-9Sb) can produce many variants with varying centromere sizes and centromeric DNA sequences. In derivatives of TB-9Sb, we found a de novo centromere on chromosome telo-3-3, which has no canonical centromeric repeat sequences. This centromere is derived from a 288-kb region on the short arm of chromosome 9, and is 19 megabases (Mb) removed from the translocation breakpoint of chromosome 9 in TB-9Sb. This centromere is much smaller than normal ones but can be maintained through meiosis. The functional B centromere in progenitor telo2-2 is deleted from telo3-3 but some B-repeat sequences remain. The de novo centromere of telo3-3 becomes inactive in three further derivatives with new centromeres being formed elsewhere on the chromosomes. One such de novo centromere contains only 200-kb CENH3 binding domain. This 200-kb centromere is located 3 Mb removed from the translocation breakpoint in a new location. The deleted B centromere in telo3-3 is activated in two derivatives. Our results suggest that de novo centromere formation is more common than previously thought and can persist on chromosomal fragments without a canonical centromere providing implications for karyotype evolution.
2015-03-03 | GSE59124 | GEO
Project description:Centromeres typically contain repeat sequences, but centromere function does not necessarily depend on these sequences. In aneuploid wheat (Triticum aestivum) and wheat distant hybridization offspring, we found functional centromeres with dramatic changes to centromeric retrotransposon of wheat (CRW) sequences. CRW sequences were greatly reduced in the ditelosomic lines 1BS, 5DS, 5DL, and a wheat-Thinopyrum elongatum addition line. CRWs were completely lost in the ditelosomic line 4DS, but a 994 kb ectopic genomic DNA sequence was involved in de novo centromere formation on the 4DS chromosome. In addition, two ectopic sequences were incorporated in a de novo centromere in a wheat-Th. intermedium addition line. Centromeric sequences were also expanded to the chromosome arm in wide hybridizations. Stable alien chromosomes with two and three regions containing centromeric sequences were found in wheat-Th. elongatum hybrid derivatives, but only one is functional. In wheat-rye (Secale cereale) hybrids, rye centromere specific sequences spread to the chromosome arm and may cause centromere expansion. Thus, distant wheat hybridizations cause frequent and significant changes to the centromere via centromere misdivision, which may affect retention or loss of alien chromosomes in hybrids. ChIP-seq was carried out with anti-CENH3 antibody using material 4DS and control (Chinese Spring, CS as short).
2016-04-02 | E-GEOD-63752 | biostudies-arrayexpress
Project description:we describe a general approach for de novo design of proteins made out of repeating units that bind peptides with repeating sequences such that there is a one to one correspondence between repeat units on the protein and peptide. We develop a rapid docking plus geometric hashing method to identify protein backbones and protein-peptide rigid body arrangements that are compatible with bidentate hydrogen bonds between side chains on the protein and the backbone of the peptide; the remainder of the protein sequence is then designed using Rosetta to incorporate additional interactions with the peptide and drive folding to the desired structure. We use this approach to design, from scratch, alpha helical repeat proteins that bind six different tripeptide repeat sequences--PLP, LRP, PEW, IYP, PRM and PKW-- in near polyproline 2 helical conformations.
2023-03-17 | PXD038492 | Pride
Project description:Centromeres typically contain repeat sequences, but centromere function does not necessarily depend on these sequences. In aneuploid wheat (Triticum aestivum) and wheat distant hybridization offspring, we found functional centromeres with dramatic changes to centromeric retrotransposon of wheat (CRW) sequences. CRW sequences were greatly reduced in the ditelosomic lines 1BS, 5DS, 5DL, and a wheat-Thinopyrum elongatum addition line. CRWs were completely lost in the ditelosomic line 4DS, but a 994 kb ectopic genomic DNA sequence was involved in de novo centromere formation on the 4DS chromosome. In addition, two ectopic sequences were incorporated in a de novo centromere in a wheat-Th. intermedium addition line. Centromeric sequences were also expanded to the chromosome arm in wide hybridizations. Stable alien chromosomes with two and three regions containing centromeric sequences were found in wheat-Th. elongatum hybrid derivatives, but only one is functional. In wheat-rye (Secale cereale) hybrids, rye centromere specific sequences spread to the chromosome arm and may cause centromere expansion. Thus, distant wheat hybridizations cause frequent and significant changes to the centromere via centromere misdivision, which may affect retention or loss of alien chromosomes in hybrids.
2016-04-02 | GSE63752 | GEO
Project description:Increasing numbers of small proteins with diverse physiological roles are being identified and characterized in both prokaryotic and eukaryotic systems, but the origins and evolution of these proteins remain unclear. Recent genomic sequence analyses in several organisms suggest that new functions encoded by small open reading frames (sORFs) may emerge de novo from noncoding sequences. However, experimental data demonstrating if and how randomly generated sORFs can confer beneficial effects to cells are limited. Here we show that by up-regulating hisB expression, de novo small proteins (≤ 50 amino acids in length) selected from random sequence libraries can rescue Escherichia coli cells that lack the conditionally essential SerB enzyme. The recovered small proteins are hydrophobic and confer their rescue effect by binding to the 5’ end regulatory region of the his operon mRNA, suggesting that protein binding promotes structural rearrangements of the RNA that allow increased hisB expression. This study adds RNA regulatory elements as another interacting partner for de novo proteins isolated from random sequence libraries, and provides further experimental evidence that small proteins with selective benefits can originate from the expression of nonfunctional sequences.
2023-03-31 | PXD040161 | Pride