BIOL 200 Lecture Notes - Lecture 2: Pyrimidine, Purine, Protein Structure
Document Summary
Nucleoside = sugar + base, bonded covalently. Nucleotide = sugar + base + phosphate group bonded covalently on the sugar. We use mono/di/tri to specify the number of phosphate groups attached to the nucleoside. All these dna structures were identified in vitro (in a lab), meaning outside of the cell (not in a living cell) Z-dna is formed transiently (temporarily) after the polymerase transcribes through it, or can be adopted by short dna molecules of alternating purine and pyrimidine nucleotides. The grooves, the space , or distance , between the 2 twisted helixes of dna, allow for binding with proteins (transcription factors, dna-binding proteins, etc. ). Most of the time, proteins bind to the major (bigger) groove. I am not certain if proteins can bind to the minor grooves, but i don"t think it has been proven. Rna-dna are duplexes in which rna and dna bind together using complementary base pairing (h-bonds between the bases), the same way double-stranded dna forms.
