BIOL 200 Lecture Notes - Lecture 9: Leucine Zipper, Dna-Binding Domain, Zinc Finger
Document Summary
Biol 200 - lecture 9, molecular mechanisms of transcription activation and repression. General transcription factors = present in all genes and promoters. Transcription factors vary from one gene to another, depending on the promoters. Transcription factors are modular proteins that contain a dna binding site and an activation/repression domain. Zinc molecule binds to two cs (cysteine) and two hs (histidine) amino acids to make a loop (finger) in the polypeptide chain of the tf. The fingers have a beta pleated sheet in one side of the loop and an alpha helix on the other side of the loop. The alpha helix can interact with the dna major groove. Usually there are 3 or more fingers repeated one after the other. The motif c2h2 is the most common dna binding motif in human"s tf. In the sense that many fingers can come together.
