HOMEWORK3

   Q1:
(a)  ID:1WRP.
   AUTHOR: J.Joachimiak, Z.Otwinowski, C.L.L.Lawson, P.B.Sigler. 
   RESOLUTION: 2.2 angstroms.
   RESIDUE NUMBER: 108

(b)

the repressor without cofactor ,and the residue 77 is in the color yellow.

the repressor binds to the cofactor,
so it is able to bind to the operator(the DNA).
The cofactor is in the color blue.

This is the whole complex with repressors,operators and cofactors.
The cofactors is in the color blue and the residue 77 is in the color yellow.

(c) from the three pictures above,we can see that when the repressor bind to
    the cofactor,the shape of the repressor is changed,then the repressor is
    able to bind to the operator(DNA) on the residue 77.

  Q2:

(a)The DNA sequences are:
  E chain: TATAGTAGAGTGCT TCTATCAT.
  F chain: TATCATCTCACGAAGATAGTAA.

(b)The picture of the repressor ARC complex with the operator(DNA).

  gln9 of chain d  V.S.  a7 of chain f


  asn11 of chain d  V.S  t17 of chain e


  arg13 of chain d  V.S  g4 of chain f