Sandbox Reserved 1249
From Proteopedia
Contents |
genetics is ok
'Molecules it Interacts With and where '
The protein binds to GDP as well as the following ligands in order to promote the attachment of the protein complex to the ribosome A site.
PHOSHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER
PHENYLALANINE
MAGNESIUM ION
'Origin'
It has domains that are created in yeast (phenyl-transfer RNA) , in the heat resistant Thermus aquaticus (EF-Tu elongation factor, and can be synthetically manufactured.
'Structure'
It has 3 domains. G proteins, Elongation Factors, and the EF-Tu/eEF-1alpha/eIF2-gamma C-terminal domain. It is composed of 6 chains, which combine in alignment.
Specific are highlighted here. The ligands listed above, GDP, Phe, and Mg+2 ion each attach at these locations which are still being explored.
which play a crucial role in binding to the ribosome during translation. They form positive pockets with which negative amino acids can bind to.
'Molecules it Interacts With and where '
The protein binds to GDP as well as the following ligands in order to promote the attachment of the protein complex to the ribosome A site.
PHOSHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER
PHENYLALANINE
MAGNESIUM ION
'Origin'
It has domains that are created in yeast (phenyl-transfer RNA) , in the heat resistant Thermus aquaticus (EF-Tu elongation factor, and can be synthetically manufactured.
'Structure'
It has 3 domains. G proteins, Elongation Factors, and the EF-Tu/eEF-1alpha/eIF2-gamma C-terminal domain. It is composed of 6 chains, which combine in alignment.
Specific are highlighted here.
which play a crucial role in binding to the ribosome during translation.
'Function"
The protein complex participates in placing the amino acids in their correct order when messenger RNA is translated into a protein sequence on the ribosome by promoting GTP-dependent binding of tRNA to the A site of the ribosome. In other words, it is involved with elongation during polypeptide synthesis.
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Function
The lac repressor is a protein that inhibits transcription of the lac operon. When the lac repressor is bound, the RNA polymerase is unable to transcribe the operon. Usually, the lac operon is turned off and the lac repressor is bound. Lactose is the lac operon inducer molecule. As soon as excessive lactose builds up, the lac repressor's side chain binds to the operator of the lac operon gene, which then activates transcription of the three genes.
The repression of the lac operon is affected by non-specific binding, and the specific binding site for the lac repressor is the operator. The create interactions between the lac operon and lac repressor that mediates the non-specific interaction.
Structure
The lac repressor is a protein whose is a tetramer. The (shown in various pastel colors) are 360 amino acids in length. When the lac repressor is assembled into its active tetramer form, it has a molecular weight of 154,520 Daltons. The repressor binds to a palindromic sequence of DNA on the lac promoter at the NH2 terminus. In this molecule, the DNA is bound to a 21 base-pair symmetric DNA duplex (GAATTGTGAGC-GCTCACAATT).
Each lac repressor folds into three functional regions. The first is a tetramerization domain that links four subunits together into the functional complex. The second is a core domain that binds to lactose and other similar molecules, like the sugar mimic ONPF. The third is the headpiece, which binds to DNA.
Where it originates
The lac operon is required in E. Coli and other bacteria for the transport and breakdown of lactose. The lac1 gene in the bacteria creates the lac repressor protein that negatively regulates the transcription of the lac operon.
References
Goodsell, D. (2003). lac Repressor. Protein Data Bank Retrieved from https://pdb101.rcsb.org/motm/39
Glassman, M. (1999) The Lactose Repressor Tutorial. Retrieved from http://biology.kenyon.edu/BMB/Chime/Mat/MASTER.HTM
Kovach, T. K. (2014). Jacob-Monod: The lac operon. In Gene control. Retrieved from https://www.khanacademy.org/test-prep/mcat/biomolecules/gene-control/v/jacob-monod-the-lac-operon.
