Question

Select all characteristics of repressor proteins. Check Al That Apply Able to bind is acting elements in DNA May bind an inducer molecule that changes its conformation Mutant superrepressor proteins inhibit transcription without binding inducer Are trans-acting proteins Has the ability to bind trans-acting elements in DNA Are cis-acting proteins Regulate catabolic pathways only

Answer 1

A protein in which its binding to the operator inhibits the transcription of one or more genes

Repressor proteins can be DNA–or RNA-binding
DNA-binding repressors - block the binding of RNA polymerase to the promoter. As a result, the gene is prevented from being transcribed into mRNA
RNA-binding repressors - bind to mRNA, preventing protein translation
Examples of repressor proteins are lac repressor that inhibits the expression of lac operon in E. coli. Another is MetJ, a methionine repressor of met operon.
Repressor proteins are influenced by the presence of other molecules, such as corepressors and inducers. Corepressors are molecules that bind and activate repressors. Inducers, on the other hand, bind and regulate repressors by inducing the latter to undergo conformational change thereby decreasing binding affinity to the operator.