Tagged Questions
1
vote
2answers
67 views
PEG-silane treatment: why incubate for 18 hours at 60 degrees Celsius?
I am conducting a biochemistry-related experiment and I have been unable to understand a step which is commonly performed.
My aim in this step is to apply a PEG (Polyethylene glycol) silane layer.
...
2
votes
3answers
45 views
What biochemical molecule viewer allows for changes in amino acids and resulting tertiary structure?
I am familiar with the Jmol, Rasmol and PyMoL softwares, and was recently introduced to BioBlender. However, I am completely unaware if any of these programs (or others) are capable of loading a .pdb ...
1
vote
0answers
19 views
What is the translation termination efficiency in mammalian cells?
When I express proteins in bacteria I put at least two stop codons at the end of the gene to increase the termination efficiency. Is this the case in eukaryotic cells too? If I put a single stop codon ...
4
votes
2answers
66 views
Differences Between Protein Motifs and Protein Domains?
I am in a 300-level molecular biology class and am unclear about this concept and how to delineate motifs versus domains of proteins. Any suggestions would be much obliged.
1
vote
0answers
26 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 ...
6
votes
2answers
156 views
Why is absorbance at 280 nm for protein solution going up when I measure repeatedly?
I have been measuring my protein solutions' concentrations by diluting them in water 20 fold with a final volume of 100 uL and then measuring the absorbances of these solutions in 96 well plates with ...
0
votes
0answers
42 views
Bradford Protein Assay [closed]
Please would somebody help me to solve the following exercise:
Determine the protein concentrations of the four unknown samples (A,B,C,D) using the raw data obtained from a Bradford assay.
...
6
votes
1answer
94 views
Determining if a specific proline is cis or trans in the protein?
While peptide bonds usually adopt the trans conformation, peptide bonds to proline can exist in either cis or trans conformation. The isomerization between cis and trans is slow, and has been shown to ...
0
votes
0answers
61 views
What happens to proteins when they absorb UV? [closed]
I know that proteins strongly absorb UV at 280 nm.
I have 3 questions:
What happens to proteins when they absorb UV?
Do different proteins absorb different wavelengths ?
Does water absorb UV as ...
3
votes
1answer
149 views
Ammonium sulphate precipitation assay pH dependence
In general does the pH effect the precipitation, e.g. would a pH of 6 cause less precipitation than pH 7.5. Or are they unrelated?
4
votes
1answer
114 views
If proteins have an overall charge, how do membrane proteins traverse through the hydrophobic region of the plasma membrane?
These two concepts seem almost contradictory, proteins have a net negative charge due to the amino acids in them each having a small negative charge, yet membrane proteins are able to exist traversing ...
10
votes
1answer
220 views
How would I explain different properties of the same protein in different species?
I recently finished an experiment where I analyzed the rate of ATP hydrolysis of Heat shock protein 104 in three species of fungi. They have shown to all have different rates of ATPase activity. How ...
7
votes
2answers
147 views
How to compute properties of peptides ?
I have been tasked with writing a program for computing properties of a give set of peptides. These peptides are given as 1-letter amino acid sequences and I need to compute the following :
Length ...
7
votes
1answer
93 views
What role does a protein's size have on protein-protein interactions?
Protein-protein interactions are when two or more proteins bind together, possibly for some important biological function. Recently, I'm starting to look more into proteins, and in particular, ...
1
vote
2answers
226 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?
1
vote
1answer
142 views
Which concentration of BSA is recommended for dynamic light scattering experiments?
What is the recommended concentration of BSA to be mixed with water so as to prepare a very dilute solution in order to clearly study the intensity-intensity correlation with single scattering ?
I ...
5
votes
1answer
112 views
Are quaternary protein monomers unique to a particular protein complex?
I know that quaternary protein structures are formed exclusively via non-covalent bonds. My biochemistry professor discussed a viral capsid that is essentially one quaternary structure with 240 ...
7
votes
1answer
106 views
Protein construct design
I am trying to create some constructs of a certain protein deleting well defined domains (at either terminus) to determine interaction regions with other proteins etc., 3 constructs with varying ...
6
votes
2answers
58 views
Is there a binding affinity metric for interactions not in equilibria?
I am investigating the strength of binding of a small peptide to a protein by isolating the bound version and subjecting it to collisions with gas molecules (CID mass spectrometry) to dissociate the ...
13
votes
1answer
2k views
What effect has changing pH and salt concentration on protein complexes?
I'm struggling to find peer reviewed literature that explains the effect of changing the pH and the salt concentration on protein/protein complexes in solution. What effect does the pH and the salt ...
