E. coli trp repressor forms a domain-swapped array in aqueous alcohol.
The E. coli trp repressor (trpR) homodimer recognizes its palindromic DNA binding site through a pair of flexible helix-turn-helix (HTH) motifs displayed on an intertwined helical core. Flexible N-terminal arms mediate association between dimers bound to tandem DNA sites. The 2.5 A X-ray structure of trpR crystallized in 30% (v/v) isopropanol reveals a substantial conformational rearrangement of HTH motifs and N-terminal arms, with the protein appearing in the unusual form of an ordered 3D domain-swapped supramolecular array. Small angle X-ray scattering measurements show that the self-association properties of trpR in solution are fundamentally altered by isopropanol.
Rutgers University, Department of Chemistry and Chemical Biology, 610 Taylor Road, Piscataway, NJ 08854, USA. cathy.lawson@rutgers.edu
Catherine L
CL
Lawson
Brian
B
Benoff
Tatyana
T
Berger
Helen M
HM
Berman
Jannette
J
Carey
D019840:2-Propanol / Q000737:chemistry; D000438:Alcohols / Q000737:chemistry*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D019281:Dimerization; D004926:Escherichia coli / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins / Q000737:chemistry*; D012542:Scattering, Radiation; D014965:X-Rays; D029968:Escherichia coli Proteins
D019840:2-Propanol; D000438:Alcohols; D001426:Bacterial Proteins; D012097:Repressor Proteins; C027190:TRPR protein, E coli; D029968:Escherichia coli Proteins