Biology And Biomedical Sciences BIOL 2960 Lecture Notes - Lecture 11: Transcription Factor Ii A, Lysine, Ubiquitin
10 Apr 2016
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Document Summary
The octamer core provides a cylindrical ramp ( a tuna fish can shape) along/around which the. Histone amino-terminal tails are conserved (but are not part of the core) and are targets for covalent modifications that regulate chromatin structure and provide binding sites for proteins. Reminder: dna is acidic because of negatively charged phosphates. Histones are basic because of abundant positively charged lysine and arginine amino acid residues. Lysines in amino terminal tails can be modified by acetylation, which neutralizes the positive charge. The n-terminal tails of histones are targets of extensive modification: Think of chromatin as a compact structure that needs be that needs to be made accessible for transcription, replication, and dna repair. Core promoter: sequences immediately adjacent to transcription start point and determine where polymerase 2 initiates transcription; minimal sequences required to recruit rna. Enhancer elements: work from far away; needed for maximal promoter activity, generally involved in cell-type specific expression.
