Questions tagged [proteins]

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

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1answer
81 views

Since the matter in the brain is recycled every few days how does consciousnesses work?

Since parts of the brain are recycled every few days does that mean that materialistic theories of consciousness don't work?
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705 views

Life cycle of proteins

I try to get a picture of the life cycle of a protein (considered as a specific molecule). This is how I can imagine it: After the cell is born a protein molecule is synthesized by gene expression ...
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43 views

Can proteins structure change depending of alimentation of an organism? [closed]

In my understanding protein are built using information caring by RNA. So a given protein should always have the same structure in a given organism has the DNA of this organism does not change. I'm ...
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95 views

Etymology of vimentin [closed]

What is the etymology of the intermediate filament , Vimentin?
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241 views

The difference between the beta-sheets and the quaternary structure of proteins

My biochemistry book says that beta-pleated sheets is a form of secondary structure of proteins, and it is formed between two or more polypeptide chains. I wonder why the sentence in bold doesn't ...
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What do you call mRNAs that translate to the same protein?

For example AUAACC and AUCACG in distinct mRNAs may both be translated to the same dipeptide Ile-Thr.
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1answer
196 views

How can carnitine enter the mitochondrial matrix without OCTN2?

Some people have defects on the gene SLC22A5, giving them problems with their OCTN2 transport protein (Organic cation transport). OCTN2 transports carnitine into the mitochondial matrix where it can ...
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159 views

What are some examples of non-homologous sequences having similar functions?

I am trying to find some proteins that are non-homologous but functionally similar. However, I cannot seem to find concrete examples. Can someone please point out any resources or provide examples?
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378 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 ...
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What attaches plant cells to the cell wall?

In animal cells integrins span the plasma membrane and attach the cell membrane to the extracellular matrix. I was wondering how are plant cells attached to the cell wall? Is it just the middle ...
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The insulin protein of apes & chimpanzees [closed]

How many amino acids do the insulin protein of apes and chimanpzees compose of?!
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30 views

Can you say “screening for a” in English?

I know this is not a "Correct Use of English Forum" but I'm afraid that people from outside the field won't be able to properly answer my question. Would it be correct to say "screening for a long ...
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Do GPCRs have 7TMHs?

I've screened a non-redundant set of GPCRs acquired from UniProt. I found a handful of examples of record IDs that contain more than the 7 TMHs. For example Q89609 and P20905, both of which have been ...
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Indicators of Ras binding domain (RBD) activity in Ras effector proteins?

Ras family based small GTPase proteins usually have a Ras binding domain (RBD) in their effector downstream proteins like Raf. Roughly Ras proteins cycle between active(GTP-bound situation) and ...
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1answer
57 views

How big is the change in proteins due to alternative splicing?

How different can the proteins be that are coded from the same DNA-sequence but undergoe alternative splicing? What I am trying to wrap my head around is why we are so fixated with the DNA-sequences ...
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56 views

Visual maps of the neuronal membrane

There are lots of visual maps of the brain as a whole, especially the cortex, that show the distribution of "features" over a two-dimensional map, e.g. the Brodman areas (their morphology and their ...
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1answer
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Will a sandwich assay work with a GST 26 antibody/protein?

I have a GST 26 kda antibody, and want to use it in a sandwich lateral flow assay. Are there enough epitope regions for both antibodies to bind to the protein?
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Can one refer to pieces of proteins produced by enzymatic digestion as “enzymatic lysates”?

A Russian text I'm translating says this: The location of post-translational modification (PTM) sites was determined using the “bottom-up” approach commonly used in this field. In accordance with ...
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537 views

What is the function of cystine, cysteine, and cysteine protease?

I am not a biologist, and I have a probably dumb biological question. For some purpose, I need to understand the function of the CTNS gene, and here is the definition of it: "This gene encodes a ...
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Will a polyclonal antibody attach to proteins of different kDA?

If I have a GST 26kDa polyclonal antibody, will it bind to the GST 28kDa protein as well?
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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 ...
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Multi-protein drug treatments

Apologies if this an obvious question - I am very new to this. I am, as of now, under the impression that multiple SNP variations interact to create multiple mutated proteins, which ultimately results ...
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358 views

What are the causes of abortive initiation?

I was reading more about DNA transcription, and it mentioned abortive initiation. The article gave no explanation as to why the phenomenon occurs. The only explanation I can think of is that it is ...
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4answers
116 views

Why do food items expire?

Why do food items and medicines expire after sometime?
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1answer
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Effect of mutation on phenotype

Is there a type of mutation that changes the phenotype of an organism, but not the protein sequence?
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2answers
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Is there a hypernym for enzymes that “cut” other molecules?

I have searched on Google for a hypernym/umbrella term that encompasses all enzymes whose function is to cut other molecules, but I have yet to find such a term. The term I am looking for would ...
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What is the distinction between deoxyribonucleases and restriction enzymes?

Both deoxyribonucleases (DNases) and restriction enzymes are endonucleases (some DNases can be exonucleases). They both break the bonds between nucleotides. Therefore, what is the difference between ...
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659 views

Pros and cons of amino acid structure vs DNA sequences for evolutionary comparison [closed]

This is an analysis question for a lab on the amino acid differences in beta globin amongst different primates, and using such differences to construct a cladogram and infer evolutionary relationships ...
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1answer
179 views

Why do humans cook animal meat

Why do humans "need" to cook animal meat? It seems there's an aspect of safety to it: are other animals (eg, house cats, dogs) not vulnerable to the same diseases we get from modern food processing ...
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33 views

Can a protein go outside of nucleus after go inside with nuclear localization signal (NLS)

To make a protein (for example Cas9, GFP...) able to enter the nucleus, we need to add a NLS tag for it. So will it able to go outside the nucleus after get inside ?
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Does cocaine bind competitively or non competitively to DAT?

I was just wondering whether cocaine, once reaching a synapse, binds to a DAT (Dopamine transporter) competitively or non competitively, or neither of them?
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555 views

Why do fully grown organisms need protein intake?

If proteins are building blocks of an organism then it makes sense why a growing organism would need an intake of them, but why would a fully grown organism need proteins (aside from those lost by ...
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In myosin II are regulatory and essential light chains calcium binding proteins or sites of phosphorylation?

According to my medical physiology by Rhodes and Bell their description is as follows: the essential light chain is necessary for myosin stability, and the other chain called the regulatory light ...
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How does hypochlorous acid inactivate viruses?

I was reading how bleach was used very widely as a disinfecting agent during the 2014 West Africa ebola outbreak and am interested in the mechanisms with which hypochlorous acid inactivates viruses. ...
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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 ...
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10k views

Do proteins generally contain phosphorus and sulfur?

I've heard that proteins generally contain six main elements - carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. I know that proteins are made from amino acids. Amino acids are composed of ...
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246 views

Does terminology for changes in membrane potential refer to additive or multiplicative change?

Is the membrane potential just the number of mV, or is it to what extent it differs from 0? For example: If the mV goes from -40 to -60, can you say that: The membrane potential decreases, because ...
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160 views

Kidney failure → Inhibition of Na+/K+ pump → Heart failure

I read in my biology book: Due to kidney failure, the concentration of K+ in the body increases. This can lead to heart failure too. But there wasn't any explanation to the mechanism of this ...
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3answers
438 views

Why do bacteria eat enamel?

What causes tooth decay bacteria or acids? I've been told that it is a combination of both but why would bacteria eat enamel? There are much easier supplies of protein for bacteria to munch through (...
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298 views

Dissolving cell pellet after sonication

I was doing a protein prep and I made a mistake. After sonicating my cells, I was supposed to centrifuge and collect the supernatant (my protein is soluble and comes in the supernatant). I however, ...
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2answers
4k views

Why are proteins always made in N to C direction?​

Why are proteins always synthesized from the N-terminus to the C-terminus? Can there be any “reverse” peptide-bond formation to synthesize proteins in the C-terminal to the N-terminal direction?
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What characteristics of the protein folding process ensure that the energy landscape is a funnel?

The folding funnel hypothesis states that the energy landscape that proteins observe when they fold is funnel shaped with a single global optima. This ensures that no matter what sequence of folds the ...
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329 views

What's the difference between prions and prion-like proteins?

If I added a prion domain to a protein, does that make the protein a prion-like protein or would it be considered a prion at that point? I'm trying to understand what prions are, how they aggregate ...
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119 views

Protein/ligand affinity databases?

Is there any database that contain binding affinities reported in litterature for different proteins and ligands? I have checked uniprot already and it does not seem to included any binding affinity ...
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348 views

If bortezomib, a cancer drug, inhibits cell proteasomes, wouldn't resulting protein aggregate in normal cells further increase the risk of cancer?

Bortezomib is an anti-cancer drug that inhibits the proteasomes of cancer cells, allowing proteins that stop cell growth to fold and perform their function. However, wouldn't bortezomib also affect ...
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String-db locally downloaded

I need a ppi network of cancer and it should have 200k to 300k proteins (nodes) As the web inteface don't allow more than 2000 ...
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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 ...
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Biogrid interaction protein network

I need a ppi network for cancer or Alzheimer . I'm using BioGrid , In the search field I can specify the gene id only , I want to know how can I make an interaction network for one of the disease ? ...
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R Stringdb bioconductor

I 'm using STRINGdb package from biconductor to manipulate String database of ppi I'm newbie and I don't find the documentation of the package useful for me . I wanna extract the associated network ...
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Retrieve the associated annotation from Uniprot

I have a dataset that I extracted using Cytoscape and STRINGAPI Hoz can I retreive the annotation of that network from uniprot as it has more than 1k proteins . and doing it manually is not possible