Polypeptide chains of amino acids folded into shape by charged R groups
3
votes
2answers
79 views
Have proteins been observed to come into existence through mutations and natural selection?
What is an example of a functional protein that has been observed (in real time) to have come into existence through mutations and natural selection (not through an existing one being made defective). ...
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?
3
votes
1answer
56 views
205 nm UV-Vis readings
Typically we determine the concentration of proteins using a 280 nm reading. However, it is reasonable to use 205 nm. I was curious about the effectiveness of this method.
3
votes
1answer
104 views
What is immunopanning (vs. immunoprecipitation and FACS)?
I had never heard the term before today. From what I can tell, it's using antibodies to purify a cell population of interest. I would appreciate more details, especially in how it differs from ...
3
votes
1answer
55 views
High protein turnover rate and protease inhibitors?
I work with mice, and I want to see what happens to some specific proteins in the mouse brain after IL-1b injection (intracerebroventricular).
I have a problem: when I measure the mRNA and protein ...
2
votes
2answers
340 views
What are the most important differences between HSP70 and HSP90?
Question originally asked on Quora. These proteins have many functional similarities, so why do cells need both to handle unfolded proteins?
2
votes
1answer
71 views
Is the protein in teardrops still attached to cells, or is it released and free-flowing?
A ScienceDaily article says that the protein in teardrops can kill bacteria.
But how does it reach the bacteria?
2
votes
1answer
33 views
Using DTNP to find free thiol groups on a protein
I've been tasked with using DTNB to find the number of thiol groups on a molecule of Bovine Serum albumin (BSA).
After measuring the absorbance, finding the concentration of TNB and calculating the ...
2
votes
3answers
46 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 ...
2
votes
1answer
42 views
Preserved alpha complementation over evolutionary time?
Has the result of alpha-complementation ever happened via mutation through evolutionary time, and been preserved in modern day organisms?
In other words, has a functional gene product ever been split ...
2
votes
1answer
44 views
How long does a tan last?
How long do melanocytes and melanosomes continue to protect DNA after UV exposure? Basically, if skin is tanned, then over the next month it is shed, will melanocytes continue to produce high levels ...
2
votes
1answer
22 views
Have novel interactions or pathways been predicted by GRN or PPI data and later confirmed by experiment?
I've been learning about the gene regulatory network (GRN) and protein-protein interaction network (PPI) recently.
I've found a huge amount of extremely interesting papers about how biological network ...
2
votes
1answer
46 views
Why glycoproteins are better than non-glycoproteins in fulfilling biological tasks?
I have just an intuition that the carbohydrate part of glycoproteins help them to fulfil those tasks like in plasma membranes.
You can also get many more receptors if you can use carbohydrates too.
...
2
votes
1answer
41 views
PTMs of proteins via mass spec?
I understand that mass spec is widely used to study PTMs like glycosylation of proteins, but how can mass spec determine correct PTM structure of say glycosylation if two glycan structures have the ...
2
votes
0answers
20 views
How to use mechanical microstrainer to extract tissue proteins from human?
Background:
There are many methods to extract proteins form human tissues out there. The majority of them use an extraction buffer containing variable concentrations of detergents and protease ...
2
votes
0answers
32 views
Where to put the gene after eukaryotic promoter for best expression levels?
As far as I know there is an optimum distance between a promoter and the gene for the best expression levels. What is that distance for common promoters like CMV, SV40? If you have a first hand ...
2
votes
0answers
25 views
Endocannabinoid Transporters - which ones are Likely to Exist and what is the Evidence for their Respective Existence?
Endocananbinoid = Endogenous Cannabinoid or CB1 and CB2 ligands.
I'm asking which endocannabinoid transporters exist and could the one answering show all the evidence for the existence of the ...
2
votes
0answers
152 views
What specifically allows alpha-complementation in beta-galactosidase?
I'm familiar with the use of alpha-complementation of beta-galactosidase with the pUC alpha-peptide and the M15 lacZ gene product, and would like to hypothetically apply alpha-complementation in other ...
2
votes
0answers
44 views
Are there examples of PTMs that add different chemical groups (and mass) to different amino acids?
I'm talking about this type of post-translational modifications. What I'm interested in is not whether some modifications can only occur on specific amino acids (that's clear), but if the nomenclature ...
1
vote
2answers
227 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
143 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 ...
1
vote
2answers
70 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.
...
1
vote
1answer
45 views
What is the difference between average and monoisotopic mass calculations of peptides?
I often have to calculate the mass of peptide sequences using calculators such as here.
I have the option of calculating the average and monoisotopic mass, but what is the difference?
1
vote
1answer
99 views
Are Bovine serum albumin, Avidin, Ficoll-70 and Dextran-70 positively charged or negatively charged?
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 ...
1
vote
1answer
39 views
How difficult is to renature a protein?
I know of Anfinsen's experiments and I'm aware that some denatured enzymes may regain their lost activity through the removal of the denaturant agent. What I'm unaware of is how rare is it for a ...
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 ...
1
vote
0answers
27 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 ...
0
votes
2answers
36 views
More proteins from diet when common cold and flu?
My coach says that I need to eat 1.2 - 1.5 grams of proteins per kilogram when I have a common cold and flu.
I normally eat one gram of proteins per kilogram, while double it when doing my exercise ...
0
votes
1answer
45 views
Why does the PR form of phytochrome exist?
I know how it gets converted because PR is more stable and when there is neither red or far red light PFR naturally converts to PR. But what is the point of it? If PFR is the biologically active one ...
0
votes
1answer
26 views
What medical and commercial proteins are made using genetically modified animals?
I have heard of recombinant technologies in micro-organisms being used to produce commercial and medically useful proteins like insulin. However, until recently, I was aware that transgenic animals ...
0
votes
1answer
28 views
SNPs mapping into protein
Starting a new project on protein-protein interactions and SNP analysis tool development. I would like to ask how does SNPs is mapped into protein? What does mapping means?
0
votes
0answers
28 views
CRISPR/Cas9 plasmid editing question [closed]
I would like to try to use the exciting new CRISPR/Cas9 system two make 2 ds breaks across about 1kb, then via homologous recombination introduce a much smaller selection marker. This done within the ...
0
votes
0answers
15 views
activate a drug using deoxycytidine kinase in vitro
I need to activate a drug similar to the way it is activated in the cell. My set of molecules called Nucleoside analog reverse-transcriptase inhibitors (NARTIs or NRTIs) need three phosphate groups to ...
0
votes
0answers
42 views
Why aren't D-amino acids used in proteins? [duplicate]
Possible Duplicate:
Why are amino acids in biology homochiral?
Why are only L-amino acids used in protein construction, and not D-amino acids?
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.
...
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 ...
0
votes
0answers
100 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 ...
0
votes
0answers
85 views
which free videos with 3d animations simulating protein processes are there? [closed]
I have found a group that creates free videos that show life within (or outside) a cell as it really is, at the near molecular level. They use real protein structures with in-molecule dynamics ...
-3
votes
1answer
93 views
How does protein help to cure wound? [closed]
I understand that the protein helps to repair body tissues. If I increase the intake of protein, would it help to cure the wound more quickly? I would like to know how does the protein reaches the ...
