Questions tagged [protein-structure]
The 3-dimensional organisation of amino acids in a protein, specifically including the secondary, tertiary and quaternary structures.
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1answer
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Protein structure prediction using PSSM? Or not?
I have been studying protein structure prediction algorithms. A lot of recent work uses something called the PSSM, the position-specific scoring matrix.
I think that what a PSSM does is to build a 2-...
0
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0answers
7 views
What is the relationship between Ca- and Na-ions and mucins and why?
According to Wikipedia
https://en.wikipedia.org/wiki/Mucin#Secretion
mucins (Proteins that form mucus) obtain viscoelastic properties by the Exchange of sodium and Calcium Ions. What is Happening ...
0
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0answers
27 views
conversion of distance matrices to pdb/coordinates
I am currently facing two transformational issues. Suppose I am given a protein's residue sequence and calpha distance matrix; is there a way to generate the 3d coordinates of the protein's residues ...
3
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1answer
70 views
Emergence of novel protein interactions by mutation of amino acids
Are there any examples of proteins that, without coming from a recent duplication event, underwent a mutation(s) that caused it to have a novel interaction with a new ligand, substrate, other protein ...
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0answers
16 views
Where can I find and download HMMTOP training set?
I would like to perform redundancy reduction for my test set for membrane topology prediction. I checked the 1998 paper and website of the HMMTOP server but haven't found any download links for the ...
4
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1answer
63 views
Backbone hydrogen bonds between adjacent amino acids in a protein?
Is it possible for two adjacent amino acids in a peptide to form hydrogen bonds between the backbone NH and CO?
Are there any examples of such situations in proteins and how common are they?
If ...
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0answers
14 views
TBX3 Protein structure and function
Is it possible for an anti-cancer monoclonal antibody to target the two repressor domains in the N and C terminal of the TBX3 protein ?
6
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1answer
174 views
Difference between prions and amyloid proteins?
Amyloid and prions are misfolded proteins, but what, if any, is the difference between them?
Is amyloid a type of prion with a fibrillar structure?
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1answer
35 views
Obtaining protein atomic co-ordinates from dihedral angles
https://en.wikipedia.org/wiki/Dihedral_angle#/media/File:Protein_backbone_PhiPsiOmega_drawing.svg
I've been reading on Protein Amino Acid Sequences and their 3D structure. It seems that the 3D ...
1
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1answer
55 views
What are the different types of helices in protein secondary structures and how do they differ?
What are the different types of helices in protein secondary structures and how are they differentiated?
In the DSSP docs, types of helices mentioned are: Alpha-Helix, Helix-3, and Helix-5.
In the ...
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0answers
45 views
Quantify Protein Denaturation with Change in Solubility
I plan to run a lab which compares the impacts of ethanol and methanol, in varying concentrations, on the denaturation of whey protein.
Change in water solubility is a good indicator of the degree ...
4
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0answers
83 views
Are there any enzymes without aromatic amino acids?
I'd like to try a new spectroscopic technique to study enzymatic reactions (which reaction doesn't especially matter, something simple and with fast kinetics like catalase would do fine - I'm just ...
2
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2answers
89 views
When does protein folding begin?
I had always assumed that protein folding is an independent activity that occurs after translation is complete. However, recently, I learned that intermolecular forces begin shaping the peptide bonds ...
2
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1answer
65 views
Is there a reason for the lack of full RTK structures?
Bocharov et al. (2013) write that
As there are no structures of full-length RTKs [receptor tyrosine kinases], we do not fully understand how different domains function together to mediate signal ...
0
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1answer
65 views
What is the length and number of the parts of a conformational epitope?
I am interested in the question whether exposure to protein A might create antibodies that also bind to protein B.
I am wondering whether, if the antigen of protein A is a conformational epitope, it ...
0
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1answer
27 views
How similar do proteins have to be to trigger the same immune response?
The title really says it all. How precise or vague is the immunity we get from vaccination or from having encountered a germ before?
Is it about protein parts that are recognised if they are ...
0
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1answer
61 views
Homology modelling of protein with two identical subunits in its quaternary structure
I am using homology modelling to assign the 3D structure of Torpedo acetylcholine receptor (Unwin 2004, 2bg9 in RCSB) to human muscle nAChR. The problem is, both Torpedo receptor, and human receptor ...
0
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1answer
44 views
is a-keratin a fully functional protein?
is a-keratin before it coils with another polypeptide, makes chains, and build intermediate fillaments a fully functioal protein?
I mean, is the single monomer of a-keratin a protein or it has to ...
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2answers
97 views
Why are the first and last amino acids of an alpha helix not hydrogen bonded?
I am studying protein structures and in alpha helix I found out that one amino acid residue's carbonyl oxygen is linked to the nitrogen of amino group of 4 residues ahead.. However the first and last ...
5
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2answers
126 views
List of proteins by number of amino acids / chain length
Is there any protein database online where I could obtain a list of proteins ordered by the length of their chains / number of amino acids, starting from the shortest, as well as to see their amino ...
2
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1answer
80 views
What proportion of proteins require chaperone-assisted folding?
I am new to the field of biochemistry (I am a chemist, actually).
I have long known the process of folding as the process that leads to the minimum energy conformation of a protein.
Now, I am ...
1
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0answers
23 views
Do the centrioles in the centrosome differ in their angle to one another?
The centrioles in the centrosome are often shown at an orthogonal angle, does this arrangement differ between samples, as in, does the daughter centriole show up in different sides of the mother ...
2
votes
2answers
93 views
What is protein secondary structure?
Could someone please clarify what is protein secondary structure:
https://en.wikipedia.org/wiki/Protein_secondary_structure
I believe I understand the primary structure, I am not sure what's the ...
1
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1answer
87 views
In centrioles, what type of fibers connect the triplet microtubules?
In a centriole, each "arm" (a triplet microtubule) is attached from its A-tubule to the C-tubule of the adjacent arm. What is the type of fiber that connects each arm ("connecting fibrils" in the ...
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0answers
374 views
Are microtubules in centrioles helical, like they are when in isolation?
Microtubules tend to be of a helical structure, do microtubules in centrioles also have a helical structure?
The centriole is composed of nine circularly arranged triplet microtubules, one complete ...
5
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4answers
173 views
Program (on Mac) to show 3D protein structures?
I have an assignment for 6th grade biology. I have to look at a 3D structure of a protein and manipulate it so it only shows the AA I’m interested in currently.
what I already did
I already looked up ...
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1answer
18 views
How does chemical shift assignment from NMR spectroscopy is translated to three dimensional structure of protein?
I am currently involved in determination of protein structure using NMR spectroscopy. As part of structure determination I have finished the chemical shift assignment. The chemical shift information ...
3
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1answer
114 views
Is the ACh receptor more permeable to sodium ions?
The AChR is permeable to sodium and potassium ions only and has a reversal potential of 0mV.
However the Nernst potentials for sodium and potassium ions is ~ +60mV and -88mV respectively. Taking a ...
1
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2answers
75 views
mRNA and Protein relation [closed]
A and B are two different proteins:
1- can they have same mrna
2- is it possible that the gene types which encoding the synthase are same ?
my answer is yes to both .
because after protein synthased ...
1
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1answer
67 views
Is protein folding symmetric with respect to reversing the sequence order?
Suppose that I have two proteins, protein A and protein B, and suppose that the sequence of amino acids of protein B is exactly the reverse of the sequence of protein A.
For example (these are made-...
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0answers
18 views
Cold adaptation at sequence & structural level
When looking for cold adaptation in unicellular eukaryotes there is not much work found. Most of the time general sequence comparative sequence analysis between marine mesophile & psychrophile ...
3
votes
2answers
368 views
What is C-terminal tryptic peptide?
A biologist wrote to me:
... C- or N-terminus,... For example, a C-terminal tryptic peptide like AGWRGSDSHSR, would be...
I don't have any idea what that is. When ...
3
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0answers
69 views
Proteins folds: relation to splicing and post-translational modification?
Is the secondary structure pattern of protein folds related in any way to alternative splicing and post-translational modification?
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0answers
78 views
How does antibody structure relate to function? [closed]
I know that antibodies have 2 binding sites (as Y shape) so they can bind to 2 pathogens for agglutination. They have a hinge, heavy and light chains, constant and variable sections on these chains.
...
3
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3answers
112 views
What are the applications of predicting the structure of proteins?
Protein molecules are very important as they are used for catalyzing almost all the chemical reactions in the cell, regulation of gene activity and provide cellular structure.
However, in predicting ...
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0answers
90 views
How a biologist attempts to explain the structure of the ribosomal proteins?
I have a Computer Science background and a minimal biology knowledge. This is the question I am asked to answer in one of the biology courses:
What would be the structure of ribosomal proteins when ...
1
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1answer
282 views
Can pymol show cartoon (secondary structure) for a pdb of multiple frames?
I am using pymol to visualise the secondary structure of protein using its cartoon representation. The ...
2
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2answers
400 views
Can VMD change its cartoon representation for secondary structure according to trajectories?
I am using VMD to visualise the secondary structure of protein.
The trajectories are from my Gromacs simulation. Firstly I use ...
3
votes
1answer
93 views
Do non-functional (‘junk’) protein sequences exist?
For DNA one can distinguish between
protein-coding DNA sequences, i.e. nucleic acid sequences inside DNA (vs. non-coding sequences)
DNA sequences that do not code for proteins but are transcribed ...
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0answers
18 views
Why glycosylation of a protein increases its non-specific binding properties?
This doubt arose while reading this website: https://www.thermofisher.com/cn/en/home/life-science/protein-biology/protein-biology-learning-center/protein-biology-resource-library/pierce-protein-...
3
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1answer
369 views
Are proteins a different shape in space?
Is the shape of a protein affected by gravity? In space, will the shape of a protein be different to what it is on Earth?
If the structure and shape is in fact affected, then would it be enough of a ...
1
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1answer
191 views
Building a PDB file from amino acid sequence of non-folded structure
I am interested in experimenting with folding simulations and algorithms for arbitrary sequences. I'm wondering if there is an easy way to convert an amino acid sequence into a PDB file for further ...
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2answers
1k views
Where on an amino acid does it attach to the protein backbone? [closed]
I've been trying to find conclusive information regarding where within an amino acid (AA) it attaches to the protein backbone (PBB). I know that, coming off of the PBB, the AA side chain is connected ...
2
votes
0answers
32 views
To which SCOP Class corresponds the following secondary structure?
I need to classify this protein into one of the SCOP class (all $\alpha$, all $\beta$, $\alpha +\beta$, $\alpha/\beta$, or small protein).
I'm having difficulties understanding the difference ...
0
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0answers
531 views
Given an amino acid sequence, how to determine the structure (helix, beta sheet etc)? [duplicate]
Assume there's a short sequence of an amino acids.
MAKMGSKKKAGHGGKEKLENMGE
I am using molecular structuring softwares to look at secondary structure. But it's ...
8
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2answers
2k views
How hard it is to determine a 3d structure of a protein?
I seeing tens of thousands of PDB files on the internet. I really want to determine a 3D structure of my protein of interest. I've heard that 3D structure determination is a complex, expensive, and ...
5
votes
1answer
321 views
How to identify a coiled coil from the amino acid sequence?
I was wondering, when we have an amino acid sequence, is it enough to check whether the positions a-d correspond to hydrophobic amino acids in order to say whether it can form a coiled coil structure? ...
16
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3answers
2k views
Is prion a term used to describe the normal form of the protein as well as the disease causing form?
I've been reading my textbook and it refers to prions as a normal protein with a helpful function but it can turn into a disease causing form. However, I look in my other textbook and it refers to the ...
3
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0answers
57 views
α-β Interfaces of Hemoglobin
I am trying to learn the interactions that hold the hemoglobin tetramer together, and the conformational changes induced at various allosteric sites. So far, what I know is this:
The tetramer can ...
6
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2answers
998 views
Denaturation of protein
Exposure of native protein to heat leads to partial denaturation of the protein due to breaking of-
a. S-S bonds
b. H-bonds
c. Hydrophobic interactions
d. Peptide bonds
After a ...
