how are antibody light and heavy chains coordinately synthesized in E.coli?
141269
they use the VDJ recombination sequence to create a variety of variable chain. the heavy chain is synthesized first, if it's working then it starts to synthesize the light chain, if not the cell undergo another VDJ recombination and if it still not working it will undergo apoptosis. same goes with the light chain, if it functions properly it will go to the lymph node and mature there. to become mature abs it has to encounter the dendritic cells and able to recognize self. if not they will die. see all of this tightly regulated mechanism is to ensure the abs are functioning properly and will not attck self.
80863
cellular and molecular biology
324206
The N-end rule pathway is a ubiquitin-dependent degradation pathway.  Ubiquitin marks proteins for degradation.  Degradation signals include a few amino acids at the N-terminus and an internal.  So, you have a point that the N-end rule pathway would be pretty pointless if all proteins have methionine at their N-termini.  \n\nBut, the polypeptide produced after translation is by no means a complete protein.  Polypeptides undergo a lot of processing including processing by an N-terminal protease that can cleave methionine off.  Without such mechanisms, the action of proteins would be severely constrained--the N-end rule pathway being one mechanism that would be constrained without such protein processing.
622581
All proteins start being manufactured by ribosomes in the cytoplasm of the cell. Sodium-potassium pump proteins will probably need to be slightly chemically modified before they are inserted into the plasma membrane, so they will contain a 15-30 amino acid long sequence at their N-terminus (in the middle of which will be a region of around 10 hydrophobic amino acids) which will target them for the endoplasmic reticulum. \n\nOnce these first signal sequence amino acids have been joined together by the ribosome, a protein called a signal recognition particle (SRP) binds to the recognition sequence on the half-synthesised protein. The SRP often halts protein synthesis. Once this has happened, the SRP-protein-ribosome complex docks onto an SRP-receptor (which also contains a ribosome receptor). The SRP then detaches from the protein, and so protein synthesis can resume. The ribosome receptor now acts as a translocation tunnel, allowing the extending protein to transverse the ER membrane. In the case of the sodium-potassium pump protein, the finished protein will emerge into the ER lumen and the pore of the tunnel will close. \n\nThe protein will leave the ER in a transport vesicle which bud off from the specialised ribosome-free regions of the ER situated adjacent to the Golga apparatus. From here they are delivered to the cis face of the Golgi and pass through the Golgi cisternae by repeated cycles of vesicle budding and fusion. \n\nFinally the protein will bud off from the trans cisternae in the golgi body and get directed to the plasma membrane, where it will get recognised and threaded through, forming a channel.\n\nIn summary: The protein is made by a ribosome, translocated to the ER, buds off in a vesicle to the golgi, and moved to the membrane.
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I assume the end of the question was "antibodies" or "antigens" and the answer is false for both.\n\nHowever there have been a few moderately successful attempts at engineering antibodies with catalytic activity. But in normal cellular physiology only specific enzymes speed up chemical reactions.
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Do you mean the molecular composition or macroscopic composition? There would be too much to post here so I suggest you visit the following\n\nhttp://users.rcn.com/jkimball.ma.ultranet/BiologyPages/B/Blood.html#formation
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In order to perform in vitro analyses, a protein must be purified away from other cellular components. This process usually begins with cell lysis, in which a cell's membrane is disrupted and its internal contents released into a solution known as a crude lysate. The resulting mixture can be purified using ultracentrifugation, which fractionates the various cellular components into fractions containing soluble proteins; membrane lipids and proteins; cellular organelles, and nucleic acids. Precipitation by a method known as salting out can concentrate the proteins from this lysate. Various types of chromatography are then used to isolate the protein or proteins of interest based on properties such as molecular weight, net charge and binding affinity. The level of purification can be monitored using gel electrophoresis if the desired protein's molecular weight is known, by spectroscopy if the protein has distinguishable spectroscopic features, or by enzyme assays if the protein has enzymatic activity.\n\nFor natural proteins, a series of purification steps may be necessary to obtain protein sufficiently pure for laboratory applications. To simplify this process, genetic engineering is often used to add chemical features to proteins that make them easier to purify without affecting their structure or activity. Here, a "tag" consisting of a specific amino acid sequence, often a series of histidine residues (a "His-tag"), is attached to one terminus of the protein. As a result, when the lysate is passed over a chromatography column containing nickel, the histidine residues ligate the nickel and attach to the column while the untagged components of the lysate pass unimpeded.\n\n\n[edit] Cellular localization\n \nProteins in different cellular compartments and structures tagged with green fluorescent protein.The study of proteins in vivo is often concerned with the synthesis and localization of the protein within the cell. Although many intracellular proteins are synthesized in the cytoplasm and membrane-bound or secreted proteins in the endoplasmic reticulum, the specifics of how proteins are targeted to specific organelles or cellular structures is often unclear. A useful technique for assessing cellular localization uses genetic engineering to express in a cell a fusion protein or chimera consisting of the natural protein of interest linked to a "reporter" such as green fluorescent protein (GFP). The fused protein's position within the cell can be cleanly and efficiently visualized using microscopy, as shown in the figure opposite.\n\nThrough another genetic engineering application known as site-directed mutagenesis, researchers can alter the protein sequence and hence its structure, cellular localization, and susceptibility to regulation, which can be followed in vivo by GFP tagging or in vitro by enzyme kinetics and binding studies.\n\n\n[edit] Proteomics and bioinformatics\nMain articles: Proteomics and Bioinformatics\nThe total complement of proteins present in a cell or cell type is known as its proteome, and the study of such large-scale data sets defines the field of proteomics, named by analogy to the related field of genomics. Key experimental techniques in proteomics include protein microarrays, which allow the detection of the relative levels of a large number of proteins present in a cell, and two-hybrid screening, which allows the systematic exploration of protein-protein interactions. The total complement of biologically possible such interactions is known as the interactome. A systematic attempt to determine the structures of proteins representing every possible fold is known as structural genomics.\n\nThe large amount of genomic and proteomic data available for a variety of organisms, including the human genome, allows researchers to efficiently identify homologous proteins in distantly related organisms by sequence alignment. Sequence profiling tools can perform more speci
1050110
A lymphocyte is a type of white blood cell involved in the human body's immune system.So they produce antibodys.Those produce the proteins.Proteins are polymers built from 20 different L-alpha-amino acids. Proteins are assembled from amino acids using information present in genes. Genes are transcribed into RNA, RNA is then subject to post-transcriptional modification and control, resulting in a mature mRNA that undergoes translation into a protein. mRNA is translated by ribosomes that match the three-base codons of the mRNA to the three-base anti-codons of the appropriate tRNA. The enzyme aminoacyl tRNA synthetase catalyzes the addition of the correct amino acid to their tRNAs.
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.....They showed that alternating deoxyribose and phosphate molecules form the twiested uprights of the DNA ladder.  The rungs of the ladder are formed by complementary pairs of nitrogen bases--A always paired with T and G always paired with C. \n\nThis is the site I got it from\nwww.dnaftb.org \n\nI hope it helps!
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The main question is: do you want to make transient or stable transfection. If you want to do stable transfections, then you will need a selective marker such as resistance to G418. \n\nSome vectors also code for a fluorescent protein such as GFP or add a tail to your protein such as a His Tag. This helps for the visualization of your protein or the purification but beware of potentially inactivating additions.\n\nYou will always have a polycloning site so what you want to find is a set of enzymes that you have in the lab in a good amount and work with them. Find the vectors that have their restriction site for the insert.\n\nAs for the promoter of use, ask around in the lab for what works the best with your cell line. It's not such a big choice.
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You will still have to read the info at the links below as it is "assumed that you have a rudimentary understanding of basic concepts of protein and nucleic acid structure, as well as enzyme kinetics and mechanisms."\n\nI digress to say that "amino acids are the principal building blocks of proteins and enzymes. They are incorporated into proteins by transfer RNA according to the genetic code while messenger RNA is being decoded by ribosomes. During and after the final assembly of a protein, the amino acid content dictates the spatial and biochemical properties of the protein or enzyme."\n\n"The amino acid backbone determines the primary sequence of a protein, but the nature of the side chains determines the protein's properties. Amino acid side chains can be polar, non-polar, or practically neutral. Polar side chains tend to be present on the surface of a protein where they can interact with the aqueous environment found in cells. On the other hand, non-polar amino acids tend to reside within the center of the protein where they can interact with similar non-polar neighbors. This can create a hydrophobic region within an enzyme where chemical reactions can be conducted in a non-polar atmosphere. Likewise, enzymes can also have polar amino acid substituents within the active site that provide a polar region in which to conduct biochemical synthesis."\n\n\n1. Structure of Amino Acids\n2. Review: Basic Concepts of Protein Structure\n3. The Basics & Definitions
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emm...is this your homework??well..it seems that the question is not from you (individually). Hmm..for more understanding, check out this website:\n\nhttp://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20101/Bio%20101%20Lectures/Biochemistry/biochemi.htm\n\nI hope it solves your dillema, good luck :)
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GGATCGA\n\nGuanine pairs with adonine and cytosine pairs with thymine.
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Antibodies are highly specific for one particular antigen, which is why the immune system (in theory) works so well. \n\nAn antibody kind of looks like a "Y". The base of the Y (the straight part) is a CONSTANT region, meaning that it is the same for every type of antibody, no matter what antigen the antibody recognizes. The constant region contains amino acid sequences necessary for the antibody to bind to other cells of the immune system, but not the antigen.\n\nThe top part of the "Y" is known as the VARIABLE region, and contains specific amino acid sequences that recognize a specific antigen. When the B cell that produces antibodies (plasma cell) is maturing in the lymph node's medullary cords, it undergoes what is called VDJ rearrangement, which means that the V, D, and J regions of the antibody protein are assembled in such a way as to make a unique antibody. There are several areas each of the V, D, and J gene, but only one is selected for each type.\n\nTherefore, a large amount of antibodies can be made that all have unique variable regions thanks to VDJ rearrangement. This means that one antibody can have one particular VDJ sequence, while another antibody has a different VDJ sequence. Therefore, these two antibodies can specifically recognize different antigens.
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I can tell you for a fact that, at least in bacterial translation systems, this phenomenon is possible, but it would require a sequence mutation to happen.\n\nIn bacteria there are ribosomal recognition sequences on the 5-prime end of the mRNA called leaders. Ribosomes use rRNA-mRNA complement sequence homology to recognize and bind, and initiate translation. If you were to mutate the upstream leader so that it was better recognized by the ribosome (in other words it would initiate translation more often) you could, in fact, decrease the amount of transcription and still get higher levels of the protein being produced.\n\nI'll admit, this is an area I haven't personally studied for about a decade, so I'm a bit out of date on the recent litterature, but as far as I remember the mechanisms for ribosomal-mRNA recognition in eukaryotes isn't as well understood as the bacterial system. I don't know if a comparable event would be possible in eukaryotic cells.
684051
immunoglobulin M or IgM...
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Proteins are composed of one or more polypeptides and polypeptides are a sequence of amino acids. every polypeptide is coded by a particular gene. during polypeptide synthesis, dna unwinds and one strand acts as a template (which is possible because of the complementary base pairs). spare bases are used to form  messenger RNA (mRNA) using the template. the mRNA moves out of the nucleus and into the cytoplasm towards the ribosomes. at the ribosomes, the polypeptide is actually synthesised. tRNA consists of an anticodon (sequence of three bases) and an amino acid. It matches its anticodon to the appropriate codon (sequence of three bases) to the mRNA. this continues with different tRNA molecules until a sequence of amino acids are formed- thus creating a polypeptide. \n\nSo, since proteins consists of polypeptides which are formed by the information in genes, in essence, a protein's structure and function is determined heavily by the gene that synthesises it.