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

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What is the relationship between protein-protein interaction networks and metabolic networks? [closed]

I am trying to find out how these networks can be linked together. I know that Protein-protein interaction networks and metabolic networks both fall under the Intra-cellular type of biological ...
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0answers
43 views

How do I identify the protein with the highest Disulfide bond density? i.e protein with highest ratio of Disulphide bonds per Peptide bond? [on hold]

I want to list all proteins in the protein database and list them by the ratio of number of disulphide bonds per peptide bond. I am not particular about the reliability of identification of ...
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0answers
24 views

Why proteins are building blocks of life? [on hold]

I like to think that normally C and H are oxidized in the nature. Yet, plants, using sun energy, break the oxigen away and build carbohydrates, like sugar/glucose. Basically, any plant is just bunch ...
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0answers
38 views

Nutritious protein substance for vitamin enhanced crop?

I am not a bio or science major, but we have a subject, like an elective on biotechnology and we were tasked to think of a product that hasn't been invented yet. My groupmates and I thought of a ...
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1answer
46 views

Is it possible that a set of functionally related proteins in a pathway fulfill different functions?

Could it be that a given pathway of enzymes (or proteins in general) may fulfill different purposes in a cell by for shifting partners? Say protein A activates B, B activates C and C has a specific ...
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1answer
21 views

IPTG and lac operator with e coli for foreign gene question

We did an experiment were we have e coli with a plasmid with a gene from another bacteria in it, and we put in IPTG in for induction. Will after looking up more about IPTG online I see it's related to ...
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1answer
31 views

Is using Hidden Markov Models to find homologues sensible in abstract, short sequences?

HMM alignment tools like hhpred excel at finding subtle homologues of folded proteins that simpler scoring techniques (such those used in BLAST algorithms) would miss. I am only looking at a small ...
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1answer
32 views

Has the protein composition (with identification) in honey and other honeybee byproducts been studied?

I am interested in studying honey and other honeybee byproducts. I have not been able to find sequence or structure records for any of the contents of honey. In particular, I want to study the ...
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1answer
121 views

Proteins: Post translational modification

I am a physicist and trying to understand some protein chemistry for a small project. Basically, amino acids combine to form proteins and after forming the primary structure, some chemical ...
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0answers
28 views

Which method would more accurately help to identify the unknown concentration of a protein sample between the A280 and the Bradford methods?

I quantified my protein using the standard Bradford method and the A280 methods and obtained values that were far off from the theoretical value of the protein of interest, and therefore was wondering ...
3
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1answer
58 views

Do these things contain amylase? [closed]

I have 10 samples of some food or other things and I need to know, if it contains amylase. I already ran an experiment with storch and iodine, but I have to make it right and my experiment must not be ...
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2answers
33 views

How do I find a protein from this DNA sequence?

I have a DNA sequence from a sequencer. How can I determine what protein is it? I tried some translator but it didn't help. What protein is this and how can I determine it? The sequence: ...
3
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1answer
102 views

What do “e” “-” “C” and “E” mean in this output?

I have given an input of this protein sequence: MEPVDPRLEPWKHPGSQPKTACTTCYCKKCCFHCQVCFTTKALGISYGRKKRRQRRRPPQGSQTHQVSLSKQPTSQPRGDPTGPKE from this website along ...
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2answers
55 views

All UniprotIDs of a cancer pathway

I need to download all uniprotIDs of a cancer pathway, say the AKT Signaling. It may be super easy, but I don't know which resource to look at since it is a new field. How/where do I find these?
2
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1answer
54 views

Thermodynamics of Forming Peptide Bonds

Which of the following shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein? A) +ΔH, +ΔS, +ΔG B) +ΔH, -ΔS, -ΔG C) ...
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2answers
72 views

What does units/mg mean for Streptavidin

I got streptavidin for surface reaction. The label says "biotin binding: 16 units/mg". What does units/mg mean? Does it mean "1 mg biotin can bind to 16 units ...
3
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1answer
66 views

How long does it take to form a peptide bond?

What is the time taken to form a peptide bond in vivo or in vitro? It isn't mentioned in my course on protein structures. I was just curious to find out if any time scale is known? Given that ...
2
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0answers
38 views

Can protein sample be made 2% Triton X-100 free?

The protein I am purifying needed an elution buffer with 2% Triton X-100. I formulated the elution buffer not keeping the CMC in mind. My goal is to make my protein sample triton free to check its ...
4
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3answers
317 views

How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids?

How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids? The book's answer is $20^{12}$. However, I disagree. This result ...
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0answers
23 views

Is this description of etiology of celiac disease correct?

There is a detailed and, to my inexpert eyes, plausible description of the etiology of celiac disease and other autoimmune disorders posted here: http://no-gluten.org/CeliacDisease.htm Is it is at ...
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2answers
8k views

Why are 3 nucleotides used as codons for amino-acid mapping in DNA?

DNA is made of 4 unique nucleotides. When coding for a protein, a sequence of 3 nucleotides is used to code for each amino acid. Why are codons 3 nucleotides in length? A related question can be ...
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1answer
53 views

Why is leucine amino acid used the most in proteins and tryptophan the least?

The amino acid leucine, is used in proteins more than others. Leucine with 9.1 percent (its average in more than 1.150 different proteins) is used most and tryptophan with 1.4 percent is used less ...
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17 views

Typical in-vivo protein concentration

I am studying RNA-binding proteins involved in RNA granules. I am searching the literature for an order of magnitude of the absolute global concentration in the cytoplasm. Although I am aware this ...
4
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1answer
161 views

Can concentration of a protein be determined from a gel quantitatively (rough estimation)?

I've got a His-tagged protein in 6M urea, 500 mM imidazole buffer that needs to be quantified before dialysis to ensure there's enough protein worth dialysing. I ran out of my elution buffer which ...
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0answers
27 views

negatively charged albumin as major carrier of acidic/negative charged drugs in blood

I reading that orsomucoid (alpha-1-acid glycoprotein) is the major carrier of positively charged (basic) drugs in the blood, while albumin carries negatively charged (acidic) and drugs with neutral ...
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5answers
137 views

Are There Rules for How Proteins Are Formed?

Proteins are formed by stringing together different amino acids. Different amino acids have different properties (such as being attracted to or repelled by water, positively or negatively charged, ...
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1answer
19 views

Exclusive microtubule minus-end labeling

Like the title explains I am looking for a way to exclusively label microtubule minus end in vivo. Looking through the literature I could not find any techniques yet. Do you have an idea?
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1answer
348 views

What can cause the bloating in high protein diet of Whey proteins?

I am thinking what can cause the swelling of gastrointestinal system i.e. bloating after high protein diet of Whey proteins. Liver does breaks those proteins to branched chain amino acids (BCAA), ...
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89 views

Circular mRNA to produce long proteins

Ribosomes can read mRNA and produce proteins, if we somehow make a circular mRNA for the ribosome to bind onto, it will make infinitely long "proteins", (since ribosomes can make very big proteins, I ...
4
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1answer
86 views

Potential to destroy viruses using prions? [closed]

Could a prion be used to sufficiently deform a viral protein in order to make the virus it is a part of incapable of reproducing? For example, take the common cold's VP1 protein and turn it into a ...
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0answers
42 views

How do PER/CRY complexes accumulate in the cytoplasm?

The Period/Cryptochrome (PER/CRY) complex is a heterodimer that transcriptionally regulates circadian rhythm. When it is phosphorylated, it is transported to the nucleus and it inhibits a ...
2
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0answers
26 views

How do I get recombinant proteins into the nucleus of mammal cells?

I know that there are Nuclear Localisation Sequencenes (NLS). They can be taken from endogenous or viral proteins and fused to the N or C terminus of my recombinant protein. Which is the best one? ...
2
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1answer
31 views

Why does the 'Positive-inside Rule' exist?

Gunnar von Heijne's Positive-inside Rule seems to have been around for a couple of decades and underpins a lot of what we know about transmembrane topology. It is used to predict the topology of a ...
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1answer
30 views

Rosetta strain with chaperones for protein expression?

I am trying to purify a protein, and I was wondering if it is reasonably straightforward to obtain E.coli cells containing: -pGroe plasmids expressing chaperones. -Rosetta plasmids with codons that ...
2
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1answer
25 views

Separation of closely-sized isoforms

I have to separate two proteins of 86kDa and 80kDa respectively, however, I just cannot get a decent separation even in 6% polyacrylamide gel. To make matters worse, these two proteins are isoforms ...
2
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1answer
77 views

What causes a polypeptide to fold into an Alpha helix over a Beta pleated sheet

I know how they fold, but what causes some polypeptide chains to preferably fold into Alpha-helix rather than Beta-sheets (or vice-versa). What force makes it fold into one conformation over the ...
4
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1answer
102 views

Mechanism of Muscle Growth

According to this video (sorry for the poor reference but it represents my level of understanding in physiology), muscle grow as a consequence of repairing micro-lesions. How are these micro-lesions ...
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0answers
30 views

Substrate specificities of GPPS, FPPS and GGPPS (isoprenoid biosynthesis enzymes)

I have some questions related to isoprenoid synthesis enzymes. Does Geranylgeranyl pyrophosphate synthase (GGPPS) contribute in Geranyl-Pyrophosphate (GPP), Farnesyl pyrophosphate (FPP) and ...
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2answers
56 views

Counting the number of hydrogen bonds of multiple PDB files

I've been trying to figure out a systematic way to count the number of hydrogen bonds for multiple PDB files. DSSP shows me the total number of hydrogen bonds when I make ...
3
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1answer
109 views

How does temperature influence the rate of protein degradation?

For computer modeling purposes, I am looking for some referenced quantitative measurements of the effect(s) of temperature on biochemical reactions. Question In particular, my question is: How does ...
1
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1answer
23 views

Does the Peptide bond produce water in our organism?

According to Wikipedia http://en.wikipedia.org/wiki/Peptide_bond , when a peptide bond is made a water molecule is released as a secondary product. So, my question is simple (perhaps silly). ...
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2answers
32 views

Resource for finding what proteins bind?

I have two lists of proteins (including phosphorylated forms). I want to determine which members of each list act on which members of the other list. What online resources exist for finding out what a ...
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2answers
140 views

Is there a difference between polarity and hydrophobicity?

From literature the two terms seem to be interchangeable when discussing protein domains and motifs. But biochemically, what are the specific differences between these two terms? For example what is ...
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1answer
167 views

Need of X or Y chromosome protein after meiosis

After meiosis each spermatid get either the X chromosome or the Y chromosome. I know that the 4 spermatids formed from 1 spermatogonia are connected by cytoplasm and so the proteins made by X or Y ...
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2answers
700 views

Importance of Double Helix DNA Structure

Gene expression involves transcribing only one strand of DNA molecule. So i was wondering what are some biological advantages of the double stranded DNA?
5
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3answers
432 views

How does protein denaturation work?

I was wondering how protein denaturation works. Are there covalent bonds, such as disulfide bridges involved, or is it based purely on non-covalent bonds such as hydrogen bonds? Why is denaturation ...
3
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1answer
156 views

Why is Cysteine and Tyrosine used to calculate a sequence isoelectric point?

Why are the amino acids - cysteine and tyrosine used in isoelectric point calculations for a protein sequence, yet neither of them are positively charged molecules? and are not used in net charge ...
0
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1answer
39 views

Epitope annotated protein

What is epitope annotted protein?? The book from which I got this term is : http://www.springer.com/biomed/immunology/book/978-1-4939-1114-1
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1answer
54 views

How can I compare the STRIDE and DSSP output files of a particular pdb file?

I have the pdb file of H-ras protein 5P21.pdb. I am supposed to compare the output of DSSP and STRIDE files after feeding this pdb file to respective servers. My question is how to make a quick ...