L2. Nucleosides and nucleotides_2024.pdf

L2. Nuceosides and nucleotides Nucleotides as building blocks of DNA and RNA If you hydrolyze DNA or RNA, (e.g. by using DNA-degrading enzymes or RNA-degrading enzymes), you get nucleotides. If you want to synthesize DNA or RNA, you need nucleotides. This lecture:...

L2. Nuceosides and nucleotides Nucleotides as building blocks of DNA and RNA If you hydrolyze DNA or RNA, (e.g. by using DNA-degrading enzymes or RNA-degrading enzymes), you get nucleotides. If you want to synthesize DNA or RNA, you need nucleotides. This lecture: nucleotide structure, naming, properties, ionization deoxyadenosine 5’-monophosphate nucleosides, nucleoside analogs (e.g. drug molecules) Nucleotide has 3 parts: base, sugar, phosphate Sugar (deoxyribose) Sugar (ribose)  Complete nucleotide molecule (with 5’ phosphate) Pentose sugar component “Deoxy” refers to Sugar Sugar (deoxyribose) (deoxyribose) the lack of hydroxyl (-OH) group on the 2’ carbon lot of rxns a blo of this occur * Sugar (ribose) hydroxyl group Sugar (pentose): You must memorize carbon numbering on ribose and deoxyribose  Complete nucleotide molecule (with 5’ phosphate) Two general types of bases: purine, pyrimidine bases attack the red & sites Bases: You must be able to identify/recognize each of the bases for the exam (you do not need to memorize the numbering scheme however)  for I just name monomer Short names and full names (in parenthesis) and abbreviations You should recognize nucleotides and know both their names and abbreviations Deoxyribonucleotides in DNA: No –OH group at 2’ position “Deoxy” in full name Letter “d” in abbreviation Ribonucleotides in RNA –OH group at 2’ position No “Deoxy” in names Thymine base in DNA Uracil base in RNA base + sugar (pentose) = nucleoside Polymer of nucleotides = nucleic acid adenosine deoxyadenosine nucleoside + phosphate = nucleotide Deoxyadenosine 5’-monophosphate  base + pentose sugar = nucleoside nucleoside + phosphate = nucleotide (polymer) string of nucleotides = nucleic acid  Phosphate can be at 5’, 3’, and/or 2’ positions Nucleoside 2’-3’ –cyclic monophosphates are formed during alkaline hydrolysis or enzymatic cleavage of RNA cAMP is a signalling molecule in many biological processes  Phosphate can be mono, di, or tri AMP: adenosine 5’-monophosphate 5 ADP: adenosine 5’-diphosphate Y I ATP: adenosine 5’-triphosphate priority & 4 group 3 You must recognize: 2’, 3’, and 5’ positions of phosphates alpha, beta, gamma phosphates deoxy (or not) at 2’ position ATP “energy molecule”  X Radioactively labeled nucleotide e.g. [a-32P]dCTP di-deoxyadenosine (which P labelled ; is if you're synthesizing DNA 5’-monophosphate B