MCB 3020C Lecture Notes - Lecture 11: Leucine Zipper, Regulon, Inverted Repeat
Document Summary
Lecture 11: dna-binding proteins and transcriptional regulation. Small molecules influence the binding of regulatory proteins to dna: turns transcription on/off. Protein-nucleic acid interactions may be site-specific or nonspecific. Most dna-binding proteins interact with dna in a sequence-specific manner. Specificity provided by interactions between amino acid side chains and chemical groups on the bases and sugar-phosphate backbone of dna. Major groove of dna is the main site of protein binding. Inverted repeats frequently are specific binding sites for regulatory proteins. Homodimeric proteins: proteins composed of two identical polypeptides. Each polypeptide has a domain (region with specific structure and function) that binds to one inverted repeat. Structure of dna-binding proteins: zinc finger, eukaryotic regulatory protein structure that binds a zinc ion, leucine zipper, contains regulatory spaced leucine residues, function to hold two recognition helices in the correct orientation. Multiple outcomes after dna binding are possible: 1. Dna-binding protein may catalyze a specific reaction on the dna molecule: 2.
