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Because the nucleotide that codes for methionine also is the "start" signal, so whenever a polypeptide starts it uses the exact same code (AUG) so methionine must start every polypeptide chain.
Wiki User
∙ 13y ago
Wiki User
∙ 11y agoIt always starts with methionine, f-methionine in particular because the codon (or three base code transcribed from DNA calling for ribosome instruction) that the ribosome recognizes as the START command dually codes for methionine. So, for a ribosome to begin translation, it searches for this start codon (which happens to be AUG) and codes for f-methionine to begin the polypeptide chain.
Wiki User
∙ 13y agoStart Codon Methionine's code is AUG which is also a start codon causing initiation of translation.
Wiki User
∙ 13y agoyes, it is the start amino acid coded for by the mRNA codon AUG.
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Do all proteins consist of one or more polypeptide chains?
Think they do consist
Do all proteins start with methionine?
Proteins have undergone post-transcriptional modifications, thus may not start with methionine after it has been modified.
What do all food chains start with?
the sun
Where does a food chains flow of energy start?
All food chains flow of energy start from the sun.
Where is tyrosine found?
Tyrosine is an amino acid that is found all over the body in its polypeptide chains and proteins. It also serves as the precursor for the catecholamine neurotransmitter dopamine in the nervous system.
Do all proteins consist of one or more polypeptide chains?
Think they do consist
Do all proteins start with methionine?
Proteins have undergone post-transcriptional modifications, thus may not start with methionine after it has been modified.
What is the starting amino acid for the beta globin protein?
Methionine. Protein translation starts at the start codon (AUG) which also codes for methionine. It means all proteins start with methionine at their N-terminus, although it's usually removed by post-translational modification.
Proteins with more than one polypeptide chain have what structure?
These have quaternary structure. This is the overall shape of all the chains combined. The 3D shape of one polypeptide chain is the tertiary structure.
What do all food chains start with?
the sun
Where does a food chains flow of energy start?
All food chains flow of energy start from the sun.
What is the componant of many lipids?
All lipids are composed of amino acids which make up polypeptide chains. Animals must have at least a small amount of lipids to survive.
The first amino acid inserted into a new polypeptide chain in eukaryotic cells is always?
The first codon is usually the start codon AUG. AUG is normally the only codon for the amino acid methionine. There are exceptions. The E.coli lactose operon contains four genes: lacI, lacZ, lacY and lacA. The amino acid sequence for all four of these genes begins with methionine. Only lacZ and lacY begin with AUG. LacI begins with GUG, which normally codes for valine. LacA begins with UUG, which normally codes for leucine. Still, the starting amino acid seems always to be methionine. Perhaps the ribosome is primed with methionine transfer RNA when it begins its translation of the messenger RNA. However, the site of translation initiation is not always at an AUG start codon. For the DNA and amino acid sequences of the E.coli lactose operon see http://www.ncbi.nlm.nih.gov/nuccore/146575?report=graph.
Where is tyrosine found?
Tyrosine is an amino acid that is found all over the body in its polypeptide chains and proteins. It also serves as the precursor for the catecholamine neurotransmitter dopamine in the nervous system.
Does science have anything to do with cosmetology?
Yes because you need to know how the hair and skin is made up, and all the different parts, how disulphide bonds are formed along with polypeptide chains.
How are protins are made?
Proteins are made by joining amino acids into long chains called polypeptides. Each polypeptide contains a combination of any or all of the 20 different amino acids
What amino acid does every newly translated protein begin with?
In eukaryotes, every newly-translated protein begins with the amino acid methionine (Met, M). This is because the start codon that signals the beginning of translation is AUG, which is also the codon for methionine - so the correlation is obligatory. The methionine may be removed during post-translational processing/modification.In prokaryotes, however, every newly-translated protein begins with formylmethionine (fMet), a methionine derivative with a formyl group added to the amino group. This difference can be used as a target for antibiotic therapy. As with methionine, the formylmethionine can be removed after translation.
