Met repressor sandbox (Beasley): Difference between revisions

← Older edit Newer edit →

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

Jimmy Beasley, Jaime Prilusky

@@ Line 7: / Line 7: @@
 ==Key structural features of the met repressor==
-The met operators in ''E. coli'' consist of tandem repeats of eight base pair sequences, AGACGTCT, known as <scene name='Met_repressor_sandbox_(Beasley)/Met_box/1'>'met boxes'</scene>. <ref name="Phillips,S" /> These met boxes vary in length from 16-40 base pairs, corresponding to two to five met boxes. The consensus sequence is highly symmetrical, with centers of inverted repeats at the center of each met box and at the junctions between them. The <scene name='Met_repressor_(Beasley)/19bp_dna/1'>self complementary 19-base oligonucleotide</scene>, that the met repressor binds to in the E. coli met repressor-operator complex at the top of the page, has the sequence 5'-TT '''AGACGTCT''' '''AGACGTCT''' A-3' which contains two tandem consensus met boxes (the met boxes are in bold).<ref name="Phillips">PMID 1406951</ref> One of the products of the methionine biosynthetic pathway is <scene name='Met_repressor_(Beasley)/Sam_ball_and_stick/1'>S-adenosylmethionine (SAM) </scene> and it acts as a corepressor. The met repressor has to bind two molecules of SAM non-cooperatively because the free repressor (aporepressor) has a low affinity for DNA.<ref name="Phillips" /> The SAM binding does not significantly change the structure of the protein, but it greatly increases the affinity for the operator. <ref name="Phillips,S" /> The following image represents SAM:
+The met operators in ''E. coli'' consist of tandem repeats of eight base pair sequences, AGACGTCT, with each sequence known as a <scene name='Met_repressor_sandbox_(Beasley)/Met_box/1'>'met box'</scene>. <ref name="Phillips,S" /> These met boxes vary in length from 16-40 base pairs, corresponding to two to five met boxes. The consensus sequence is highly symmetrical, with centers of inverted repeats at the center of each met box and at the junctions between them. The <scene name='Met_repressor_(Beasley)/19bp_dna/1'>self complementary 19-base oligonucleotide</scene>, that the met repressor binds to in the E. coli met repressor-operator complex at the top of the page, has the sequence 5'-TT '''AGACGTCT''' '''AGACGTCT''' A-3' which contains two tandem consensus met boxes (the met boxes are in bold).<ref name="Phillips">PMID 1406951</ref> One of the products of the methionine biosynthetic pathway is <scene name='Met_repressor_(Beasley)/Sam_ball_and_stick/1'>S-adenosylmethionine (SAM) </scene> and it acts as a corepressor. The met repressor has to bind two molecules of SAM non-cooperatively because the free repressor (aporepressor) has a low affinity for DNA.<ref name="Phillips" /> The SAM binding does not significantly change the structure of the protein, but it greatly increases the affinity for the operator. <ref name="Phillips,S" /> The following image represents SAM:
 [[Image:SAM.png]]