Biopolymers consisting of amino acids that fold into 3D shapes and perform a large number of functions in living organisms.

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Pectinase Enzyme Assay

I am working on pectinase enzyme assay. I incubated 900 ul of substrate for 10 minutes in the water bath, followed by adding 2ml of DNSA reagent, then 100ul of enzyme extract added finally i read the ...
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1answer
57 views

What regulates the timing of the motion of molecular machines during DNA Replication?

This question is about this video I found on Youtube. I just want to know what is the mechanism which regulates the timing of motion of the parts of these molecular machines. I know that those big ...
2
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1answer
35 views

What is the biding site code recognized by the parts of the spliceosome

Another question about another Youtube video. At 0:50, the splicing process begins to remove the non-coding section of the DNA (intron), so the different parts of the spliceosome attach to the borders ...
3
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1answer
123 views

How to remove bad lanes in ImageJ Westernblot analysis

I use ImageJ to do an analysis of a Westernblot Image. If everything goes as wanted the workflow is fine. But if I do something wrong creating a lane there is no undo for a lane and also no way to ...
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18k views

What is the difference between HPLC and FPLC and why is FPLC preferable for protein purification?

I've used HPLC (high performance liquid chromatography) before (once, so I'm barely even qualified to know what it stands for) so I was surprised when my labmate told me she would be using an ...
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997 views

Difference between Condensin and Cohesin proteins?

The chromosomal DNA is stacked with help of cohesin and condensin protein in which particular manner? Can cohesin be said to form kinetochore? How would they vary exactly? The terms are so narrowly ...
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3answers
134 views

More entropy: Atom or Macromolecule? [closed]

A question that appeared on my last exam was : Which of the following has greater entropy A) An atom B) A macromolecule The question doesn't specify anything else(i.e. type/size of atom or ...
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1answer
69 views

What I can do in order to improve the folding of the protein?

I am struggling with the expression of the certain protein. It seems that it is not properly folded and thus, it is not active. I tried to express it at the lower temperature and for the longer time, ...
3
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1answer
75 views

How to recognize a conserved motifs of the protein

I would like ensure that my reasoning is correct. Assuming that I know the aminoacids sequence of the protein of interest. I can't say anything about the structure looking only at the aminoacids ...
2
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2answers
84 views

Turning publicly available genome data into proteins

I'm a computer scientist who is starting to dabble with biology. My eventual goal is to model different kinds of cells with a computer program. As of right now, I'm just trying to take some smaller ...
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1answer
63 views

To what extent is it possible to understand if a bacteria can produce a protein? (in silico only!)

I have to answer a question about a sub-task of my thesis: Can the bacteria X produce the protein Y? I searched of course Google and BLAST. There is no data supporting that this specific bacteria ...
2
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1answer
50 views

Formation of peptide bond..?

Proteins peptide bond is made by condensation process in which a molecule of water is released and according to this process it is not favorable in water systems than how peptide bond is formed by ...
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1answer
32 views

What does the term 'modified residue position' in phosphorylation mean?

Does it mean the position of the amino acid in the protein sequence, or something else? For example, I came across the phrase "S 368 phosphoryation" where S is the modified residue and 368 is the ...
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3answers
106 views

Which point mutations in proteins are OK, and which cause significant change?

I heard that some point mutations in proteins are OK, like from alanine to glycine (I'm not sure, it's just an example), some will change the protein significantly. I want to understand deeper but ...
4
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1answer
117 views

What Proteins Are Universal To All Life Forms?

According to National Geographic, there are 23 proteins that are common to all life forms: All species in all three domains share 23 universal proteins, though the proteins' DNA ...
5
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3answers
213 views

Protein structures given in PDB and SNP's

There are millions of proteins given in PDB, the sequence for which we can download in FASTA format. There are also hundreds of SNP's given in NCBI dbSNP. My question is whether the proteins in PDB ...
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2answers
358 views

Why digest proteins into peptides for Liquid Chromatography - Mass Spectrometry?

Digesting (trypsin or whatever other proteolytic enzyme) proteins generates multiple peptides so the degree of complexity of the sample, at the peptide level, increases a lot. In addition there is ...
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1answer
65 views

level of organisation of proteins

Is there any disulphide bond in a quaternary structured protein? If yes, please provide examples. In tertiary structured proteins, what is(are) the most important characteristic(s) of tertiary ...
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2answers
104 views

alpha tubulin molecular weight problem

Is there any academic reference that shows α-tubulin is around 50-55 kDa? The only thing I found is some data sheets from companies. I need the real reference.
2
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2answers
98 views

What are the naming conventions for mutations of proteins?

I have been reading about Maltose Binding Proteins. Mutant forms of the molecule seem to be named MalE_ where the _ represents a number, for example MalE36 or MalE50. Please can someone explain the ...
3
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2answers
200 views

What happen's to a virus's capsid after it injects its genetic material into the host cell?

After a virus (one of the varieties which infects the cell via injection and not endocytosis) injects its genetic material into the host cell, what happens to its protein coat? I would guess that it ...
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2answers
300 views

How are proteins formed?

Somewhere, I have read that we need to consume proteins to make amino acids to make new proteins. What does it suggest? How do we make proteins from proteins?
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1answer
29 views

How are cyclic hormones characterized?

I have a question regarding the description of a subset of peptide hormones, called cyclic hormones. Two examples of cyclic hormones would be somatostatin and melanin-concentrating hormones. I know ...
3
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1answer
154 views

What do the Clustal Alignment Symbols Mean?

Occasionally I will run protein alignments on peptide families and I can never remember what the symbols mean to show degrees of identity. What do they mean?
5
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1answer
74 views

Selective Androgen Receptor Agonist

I'm looking for an inducer that strongly activates the androgen receptor, but not the glucocorticoid receptor that is not DEA regulated. I know that SARMS (Selective Androgen Receptor Modulators) are ...
3
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1answer
42 views

The use of proteins in memory creation

I have very limited knowledge of how the human memory works as I think, at this time, most people do. However, I have been reading and some articles which say, and I quote the article just linked ...
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1answer
109 views

Color van der waals bonds in swiss PdbViewer

I'm trying to color certain amino acid's van der waals bonds as in the following picture: can anybody please describe the steps to accomplish that?
2
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1answer
284 views

Are Bovine serum albumin, Avidin, Ficoll-70 and Dextran-70 positively charged or negatively charged? [closed]

Bovine serum albumin, Avidin, Ficoll-70 and Dextran-70,are they positively charged or negatively charged ? And which other solvents can be used as a substitute to water for preparing solutions in each ...
3
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1answer
140 views

How to wash the column during protein purification with GST tag?

I have been working with GST tagged proteins for the last 4 years and after loading the cell lysate into the column I was washing it with 20-30 column volumes of PBS and sometimes my proteins were ...
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1answer
36 views

Evolutionary rationale behind migration proteins

Tumor cells are able to migrate due to specific migration proteins. What is their evolutionary origin? Or are they simply deregulated?
2
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1answer
36 views

Protein Conformation Modeling

I'm interested in learning about computational modeling in biophysics. I have heard some amount about people modeling proteins as a network of ideal springs to examine things like conformation ...
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1answer
56 views

Curious about Brazzein

What is in compound "Brazzein" that it makes it 2000 times more sweeter than sugar? Can anyone please explain the science behind it?
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2answers
230 views

What are the functions of disulphide bonds?

What are the functions of disulphide bonds between amino acids in proteins or peptides?
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1answer
41 views

conservation of C-peptide sequence in the guinea pig

Where can I compare the C-peptide sequence of guinea pig with human or mouse? I am also interested in finding whether the guinea pig has insulin 1 and 2 to know whether I could use an anti-C-peptide 1 ...
2
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1answer
354 views

What is optical density in Lowry's protein estimation method?

I have a few questions: What is an OD value? Why do we use blank solution in Lowry's protein estimation method? If The OD of a protein is 0.01, what does it mean? Thanks in advance.
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13 views

To decrease the amount of proteins in the lymphatic drainage for short term

I am looking for some mechanism which can decrease the amount of proteins in the lymphatic drainage only for short term. Assume there is no flow between capillaries and lymphatic system because the ...
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1answer
26 views

fibrinogens and fibrins - are they the same molecule?

Some proteins are "activated", like fibrinogens; they are turned into fibrins by thrombins, and then the fibrins can aid in blood clotting. Are fibrinogens and fibrins the same molecule, just in ...
8
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1answer
881 views

Is there a protein in the eye that gets kinked by photons and shipped down to the liver to get un-kinked?

My friend made the claim that there exists a protein in your eye responsible for vision. This protein is sensitive to different wavelengths of light, and when it gets hit by the right wavelength, it ...
2
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1answer
2k views

Why do three nucleotides code for one amino acid? Why not 5 nucleotides? [duplicate]

We all know why there are 3-base codons, and why there aren't any 2-base codons. But why is there not a 4-base a 5-base codon?
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2answers
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Can protein precipitate out in alcohol during DNA extraction?

In common lab sessions to extract DNA from strawberry or cheek cells, will there be protein contaminating the DNA extract in alcohol? If so, how can we prevent protein from precipitating out of the ...
3
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1answer
77 views

Function of heparin and dextran sulfate for removing proteins

From this article : The reaction was terminated and the histones, and most nonhistones, were removed by adding the nuclease-treated chromosomes to a solution containing dextran sulfate (2 ...
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1answer
38 views

If a gene altered causes cancer and creates a protein for cancer can the new protein be isolated in some way?

In the above title question, can the protein thats altered not be isolated (to separate out from other proteins) somehow? Is there nothing that can bind to the specific cancer proteins that will not ...
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1answer
122 views

how do they identify different protein chains?

Can someone please explain how different protein chains occur exactly? I'm not talking about the side chain, but the protein chain which is typically labelled as A,B,C etc in the PDB. I'm curious as ...
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2answers
166 views

pI and pH relationship in context of ion exchange protein purification

I am confused about relationship between isoelectric point and pH in context of ion exchange protein purification. Why we cannot use this method for protein with pI below 7? Thank you very much for ...
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2answers
106 views

Conserved proteins are non immunogenic

I read that proteins that have been highly conserved are non-immunogenic. Why is it so ? What is the special thing that makes it non immunogenic(antibodies against them are hard to make) ?
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1answer
78 views

Length differences between physically interacting proteins

What can be said on the length differences between interacting proteins? Are they usually of similar sequence lengths or not at all?
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1answer
75 views

How to parse SCOP parseable files PDB residue identifiers?

I am trying to parse the SCOP parseable files, specifically dir.des.scop.txt ver 1.75. But, I have been facing problems with the PDB residue identifiers in the file. This is a tab limited file and the ...
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3answers
190 views

What are some examples of genes that code for multiple proteins?

The title pretty much says it all. It is widely taught that a gene in a eukaryotic system could produce more than one protein due to post-transcriptional modification, but I do not believe I have come ...
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1answer
65 views

Enzymatic Protein Deglycosylation of TCL

I've done O- and N- linked enzymatic deglycosylation of purified and lyophilized proteins. Following some modifications to the manufacture's protocol, I had great results. I now want a student to ...