DNA regulatory proteins

The three-dimensional structures of about 20 regulatory proteins have been determined in four cases the structures of the specific DNA-regulatory protein complexes have also been determined. 

Examination of DNA-regulatory protein complexes have permitted reasonable guesses to be made about the precise nature of the contacts between amino acid side chains and DNA in many cases. Figure 30.27 illustrates three examples One for the 434 phage repressor (fig. 30.27a), one for the A cl repressor (fig. 30.27b), and one for the trp repressor (fig. 30.27c). In all cases only half-sites are depicted because symmetry considerations dictate that the two halfsites should have virtually identical structures. 

The amino acid sequences of mammalian DNA regulatory proteins suggest the existence of at least three different types of activation domains Acidic, glutamine-rich, and proline-rich. 

The three-dimensional structures of most DNA regulatory proteins that have been... 

Transactivation. Protein synthesis is initiated or inhibited by the action of the activated GR on DNA. The use of glucocorticoids leads to antiinflammatory effects by first controlling gene expression, which subsequentiy leads to the synthesis and/or suppression of inflammation regulatory proteins. 

Most sequence-specific regulatory proteins bind to their DNA targets by presenting an a helix or a pair of antiparallel p strands to the major groove of DNA. Recognition of the TATA box by TBP is therefore exceptional it utilizes a concave pleated sheet protein surface that interacts with the minor groove of DNA. Since the minor groove has very few sequence-specific... 

It is now apparent that bacteria have developed resistance to heavy metals and the detoxifying process is initiated and controlled by metallo-regulatory proteins which are able selectively to recognize metal ions. MerR is a small DNA-binding protein which displays a remarkable sensitivity to Hg +. The metal apparently binds to S atoms of cysteine and this has been a major incentive to recent work on Hg-S chemistry. 

The 80-bp right operator. Op, can be subdivided into three discrete, evenly spaced, 17-bp cis-active DNA elements that represent the binding sites for either of two bacteriophage A, regulatory proteins. Impor-... 

Detailed analysis of the lambda repressor led to the important concept that transcription regulatory proteins have several functional domains. For example, lambda repressor binds to DNA with high affinity. Repressor monomers form dimers, dimers interact with each other, and repressor interacts with RNA polymerase. The protein-DNA interface and the three protein-protein interfaces all involve separate and distinct domains of the repressor molecule. As will be noted below (see Figure 39—17), this is a characteristic shared by most (perhaps all) molecules that regulate transcription. 

SEVERAL MOTIFS MEDIATE THE BINDING OF REGULATORY PROTEINS TO DNA... 

The specificity involved in the control of transcription requires that regulatory proteins bind with high affinity to the correct region of DNA. Three unique motifs— the helix-turn-helix, the zinc finger, and the leucine... 

THE DNA BINDING TRANS-ACTIVATION DOMAINS OF MOST REGULATORY PROTEINS ARE SEPARATE NONINTERACTIVE... 

DNA binding proteins. Since these proteins have no homology with proteins of the other families of transcriptional regulators, they define a new family of regulatory proteins. 

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