Questions tagged [proteins]

Questions relating to proteins, the chains of amino acids that form three-dimensional structures carrying important functions of life. Protein sequence, structure, similarity, domains, etc.

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11
votes
1answer
104 views

What are the optimal parameters for docking a large ligand using Hex?

I'm looking to dock a large ligand (~90kDa) to a receptor slightly larger receptor (~125kDa) using Hex. If anyone is familiar with docking large structures, are there any recommended parameters for ...
10
votes
4answers
725 views

How can I build a protein network pathway from a gene expression quantification file?

Assume I have found the top 0.01% most frequent genes from a gene expression file. Let's say, these are 10 genes and I want to study the protein protein interactions, the protein network and pathway....
8
votes
2answers
659 views

Phyre2 vs ITasser, completely different models generated

Does anyone have experience generating pdb structures with Phyre and ITasser online tools. The results generated from each given the same amino acid sequence input are very different and I am ...
7
votes
0answers
69 views

Minimizing particle-flow grid mapping time of a protein surface using spherical-coordinates and differentiation encoding [closed]

This is an interesting problem - I was wondering if anyone has a creative solution. So I have a vector of vertices representing atoms in a protein, as well as 6 variables containing the absolute ...
6
votes
3answers
71 views

Do any publicly available databases detail protein structure and functional domains?

I am interested in finding a database that takes a gene or protein name as input (possibly with the option to specify transcript) and gives information about the protein's functional domains in terms ...
6
votes
2answers
110 views

How to determine a protein's cellular location based on its sequence?

I am wondering about the appropriate workflow to determine a protein's cellular location based on its sequence. Let's say I have a sequence like this from a fasta file ...
6
votes
2answers
1k views

How to select a cutoff for interaction confidence in STRINGdb?

I have a list of 100 genes that are called as hits in a genetic screening. I want to have a network of the interactions between the proteins of these 100 genes. I am using both STRINGdb web and its R ...
6
votes
3answers
460 views

Calculating the charge of a peptide computationally

I was wondering how I can calculate the charge of a protein peptide (e.g. "RKTTLVPNTQTASPR") computationally in R or another tool.
6
votes
1answer
149 views

Verify a predicted protein in one genome in a different genome of the same species

I have two genome assemblies of the same non-model species, call them Assembly 1 (generated from Illumina data) and Assembly 2 (generated from PacBio data). For Assembly 1, I also have predicted ...
6
votes
1answer
58 views

How do I compare measured ratios to calculated ratios in peptide mass spectrometry?

I have two different sets of internal standards in a sample (1), and a sample (2) with these internal standards as well as about 30 peptides. Each peptide has one of each of these kind of standards. ...
5
votes
3answers
1k views

How to translate amino acid sequences to Nucleotide sequences

I want to convert a list of fasta ( protein sequences) in a .text file into corresponding nucleotide sequences. A Google search gives me result of DNA to protein conversion but not vice versa. Also, I ...
5
votes
3answers
474 views

How to determine the primary Uniprot accession number from a set of accession numbers?

Given a list of Uniprot IDs that are linked to an Ensembl gene ID, is there a way to systematically determine the UniProt accession corresponding to the protein product of the gene's primary ...
5
votes
1answer
70 views

How can I dock a protein to a nucleic acid?

I have a protein of interest and I would like to now how it interacts with RNA. I have structures of both molecules. What tool can I use?
5
votes
1answer
37 views

How to query a network for a bacterium, specifically Streptomyces caatingaensis or Streptomyces thioluteus?

I have a list of gene/protein IDs and I could not query a network using String, BioGrid, Intact and IIS, for Streptomyces thioluteus. The bacteria I am working with is the Streptomyces caatingaensis. ...
4
votes
2answers
25k views

How to scale the size of heat map and row names font size?

I have an expression data matrix (120X15; 15 samples and 120 genes), my heatmap looks blurred and raw names (gene names) looks very small and can not read. How can I improve my scripts? Here is the ...
4
votes
2answers
258 views

If I modify a PDB file with a specific mutation, how to minimize energy?

I have a series of proteins that are all phylogenetically related. Only one of this proteins is currently X-ray crystallized. Is it valid to modify the reference PDB file (I mean by hand) to match ...
4
votes
4answers
138 views

What are the standard ways to visualize protein-protein or gene-gene interactions?

I would like to visualize this interaction list. Is there an online/web based way to do it? Is there a way to analyze the data? Assuming I have exported the list into lines such as: ...
4
votes
1answer
101 views

What origins for virus HIV1?

What origins for virus HIV1? This is the alignment of a small part of the POL protein of the HIV1 virus GenBank KU749412.1, with the POL protein of the Visna virus GenBank L06906.1 ...
4
votes
1answer
332 views

How could I match atom orders between a .mol2 and a .pdb?

When I was drawing conformation of Autodock result, I noticed that Autodock generated pdbqt from dlg has some structural problem (e.g. Benzene ring missing), and wants to correct this. However I ...
4
votes
1answer
106 views

Retrieval of genomic position by using biomaRt package

I have a list of several protein names, their primary gene name and their amino acid sequence (as extracted from the 'SEQRES' section in their corresponding PDB files). I'm looking for the genomic ...
4
votes
2answers
84 views

ROC analysis, CAFA 2 experiment

My question is about ROC curves used in CAFA2 experiment. In this paper they used the ROC analysis for the term-centric evaluation. In order to perform ROC curve analysis we should have a continuous ...
4
votes
2answers
131 views

Cross-reference with PDB database

I have a list of several thousand proteins and their UNIPROT IDs. I'm looking for an efficient method of cross-referencing it against the PDB tertiary structure database, and get a list of those ...
4
votes
1answer
37 views

Identity plus Similarity Interpretation

I am helping a colleague to interpret protein multiple sequence alignment results. My colleague used a third-party proprietary solution (I know...) to calculate the alignment, and one of the resulting ...
4
votes
1answer
58 views

Software to produce a table of post-translational modifications from a peptide list

Does anyone know if there is a program/library/script in R or Python that takes as input a list of proteins/peptides and a list of post-translational modifications (PTMs; like oxidation of methionine ...
4
votes
1answer
69 views

Using signal peptide and the expression levels of signal recognition particle in secretome analysis

I have not found any work which investigates assessment of differences in levels of secreted proteins by taking advantage of differential expression of the genes which mediate the secretory pathway. ...
4
votes
1answer
61 views

Is there a modern alignment tool tailored for transmembrane regions?

I am looking for a project or tool that allows programmatic pairwise alignments of proteins but that takes care with transmembrane regions of proteins. TM regions are traditionally too information ...
3
votes
2answers
183 views

Why are some of the gene peptides returned by biomaRt missing an asterisk in the end?

Note: this question has also been asked on BioStars I am getting peptides using biomaRt library in R for the gene 'BRCA1'. 27 different aminoacid sequences are returned, and 12 of those have an ...
3
votes
2answers
276 views

Influence of pH on protein peptide mass

I'm using the Peptides package in R to calculate the mass of peptides with the mw() method. The thing is that I want to calculate them for different pH values, and thus I wrote this little function to ...
3
votes
3answers
122 views

Database for proteome-wide predictions of protein structures

Accuracies of protein structure predictors have improved quite a lot in recent years. Algorithms such as Rosetta have gotten robust enough to predict structures of large number of proteins. However, I ...
3
votes
2answers
162 views

How to find/build the evolutionary history of a protein from its sequence?

I'd like to build the evolutionary history of a protein, given its sequence. Namely, given a FASTA entry how can I build an evolutionary tree? Here is the 5wxy protein as an example: ...
3
votes
1answer
190 views

CCP4 file to a Python 3 numpy array or similar workaround

I would like to merge together several ccp4 formatted density maps (and do a few minor things). So ideally I would like to open the ccp4/mrc files as numpy arrays in Python 3 and save the array as a ...
3
votes
1answer
33 views

How to filter the PDB for single-domain proteins with full length 3D-structures solved

I am trying to reproduce a machine learning model that has been developed here. As one of the datasets, they use single-domain proteins with full length 3D-structures solved. Since I don't have a ...
3
votes
3answers
93 views

How to get the product of a CDS

I need the name of the protein in /product="protein_name" using bash commands. Beware, there is a lot of whitespace between lines. ...
3
votes
1answer
74 views

Determining position of side chain hydrogen in glycine residues from coordinates of backbone atoms

I have a dataset of pdb-format protein structure decoys/models generated by tertiary structure prediction programs. Many of these are missing hydrogen atoms. Specifically, I'd like to determine the ...
3
votes
1answer
41 views

Folded Protein Chunk Dimensional Classification?

Are there known dimensional measurements for the classification of folded proteins given a starting chunk/domain as defined by something like the clustering functionality of MSM Builder? Examples of ...
3
votes
1answer
112 views

Building network for biomarker interaction analysis

I am looking for advice on how to best approach a problem I am faced with. I have a dataset of numerous degradative biomarkers, clinical information and various other measures (from clinical trials)....
3
votes
1answer
73 views

protein secondary structure matching/comparison scoring

I want to compare two secondary structures of aligned proteins. I do not know exactly how to do it well. Example: ...
3
votes
1answer
1k views

Searching for start and stop codons for protein sequencing of contigs

I need to convert contigs into their respective protein sequences given a reference genome (i.e. I need to take a substring, whose position is already known on the string, and I need to locate the ...
3
votes
0answers
29 views

Convert .smp from CDD into HMM file

Is there a method or tool to convert a .smp file from CDD (Protein Domain File) into a HMM file? I downloaded the CDD files from the FTP site and am more familiar with domain searching with the HMMer ...
3
votes
0answers
102 views

How to assign the best gap penalty and gap extension penalty using BLOSUM65

For an assignment I must do a pairwise optimal local alignment using BLOSUM65 and five protein sequences. The algorithm I want to use is the Smith-Waterman. Context protein sequencing using Blastp: ...
3
votes
0answers
76 views

Can VMD change its cartoon representation for secondary structure according to trajectories?

I am using VMD to visualise the secondary structure of protein here. The trajectories are from my Gromacs simulation. Firstly I use ...
3
votes
0answers
167 views

Map domain names from UniProt bed files to domain accessions

I want to get a bed file mapping human protein domains to the human genome. UniProt actually offers such a thing here. The problem, however, is that the file doesn't include any kind of domain ...
2
votes
2answers
805 views

Protein folding problem model for quantum computers?

It's supposed that quantum computers could help to find the native state of all human DNA proteins. Does anyone know how to formulate the protein folding problem into a decision problem solvable ...
2
votes
1answer
32 views

How to interpret amino acid representation

What is the difference between C383S and C383A? For C383S, does it mean Cysteine(C) position 383 in the sequence and its next amino acid connect to it is Serine(S)?
2
votes
2answers
60 views

Genomic coordinates of predicted binding pocket

I would like to know the genomic coordinates of a proteins ligand-binding pocket. For example, on this PDB page you can see that there is xray crystallography data for how CYP2C9 interacts with two ...
2
votes
1answer
54 views

Mining documents for nucleotide and peptide sequences

The text mining literature has an emphasis on identifying and normalizing gene names, mutations, pathways, concepts, and so on. I haven't been able to find much, however, on methods for extracting ...
2
votes
1answer
50 views

PDB residue numbering

The residue numbering in PDB (in my understanding) coincides with UniProtKB align. However, this might not be consistent with that in PDB fasta file. To complicate it further, UniProtKB align can be a ...
2
votes
1answer
103 views

Human Herpes Virus, fusion motif in protein vs. SARS-CoV-2?

Is it possible that the fusion with cell propriety of Human Herpes virus, I see X14112.1 in GenBank is due to protein UL36 (tegument of virus) starting in linear position 2685 ??? ...
2
votes
1answer
44 views

Protein misfolding

I am looking for literature on protein and RNA mis-folding. I am on the computational/biophysics side, and what interests me are the practical applications: diseases caused by misfolding, drug ...
2
votes
1answer
57 views

Principle of TMT Tags in Multiplex Proteomics

I am new to proteomics research and analyzing mass-spec data. I am trying to learn more about the theory/principle of TMT tagging (a type of isobaric labeling) coupled with LC-MS/MS spectrometry. I ...