Lambda repressor: Difference between revisions
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<StructureSection load=3bdn size=' | <StructureSection load=3bdn size='350' side='right' scene='Bacteriophage_Lambda_Repressor_cI/Homodimer_bound_to_dna/3' caption='Lambda repressor cI protein dimer complex with DNA (PDB code [[3bdn]])'> | ||
== Introduction == | == Introduction == | ||
'''cI''' is a transcription inhibitor of bacteriophage Lambda. Also known as '''Lambda Repressor''', cI is responsible for maintaining the lysogenic life cycle of phage Lambda. This is achieved when two repressor dimers bind cooperatively to adjacent operator sites on the DNA. The cooperative binding induces repression of the ''cro'' gene and simultaneous activation of the ''cI'' gene, which code for proteins Cro and cI, respectively (Stayrook et. al, 2008). | '''cI''' is a transcription inhibitor of bacteriophage Lambda. Also known as '''Lambda Repressor''', cI is responsible for maintaining the lysogenic life cycle of phage Lambda. This is achieved when two repressor dimers bind cooperatively to adjacent operator sites on the DNA. The cooperative binding induces repression of the ''cro'' gene and simultaneous activation of the ''cI'' gene, which code for proteins '''Cro''' and '''cI''', respectively (Stayrook et. al, 2008). | ||
==Structural Overview== | ==Structural Overview== | ||
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==N-Terminal Domain (NTD)== | ==N-Terminal Domain (NTD)== | ||
The NTD Lambda repressor (PDB entry [[1lmb]]) consists of the first 92 amino acid residues of the protein and contains the <scene name='Bacteriophage_Lambda_Repressor_cI/Ntd_spacefill/1'>DNA-Binding Domain</scene> (Stayrook et. al, 2008) of the protein. The secondary structure of the NTD is a compact conformation of six alpha-helices. This secondary structure shows weak self-association, which is purported to aid in formation of the dimeric unit. The DNA-binding motif utilized by Lambda Repressor is a <scene name='Bacteriophage_Lambda_Repressor_cI/Hth_motif/1'>Helix-Turn-Helix</scene> (Beamer and Pabo, 1992). The Helix-Turn-Helix motifs of two dimerized NTDs are illustrated in red to the right. | |||
</StructureSection> | |||
== 3D Structures of lambda repressor == | == 3D Structures of lambda repressor == | ||
See [[Bacteriophage repressor]] | |||
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==References== | ==References== | ||
