Chapter 24 Nucleotides, Nucleic Acids, and Heredity Nucleotides, Nucleic Acids, and Heredity.
Nucleotides & Nucleic Acidschemistry.creighton.edu/~jksoukup/lec24part2.pdf · Nucleotides &...
Transcript of Nucleotides & Nucleic Acidschemistry.creighton.edu/~jksoukup/lec24part2.pdf · Nucleotides &...
Nucleotides & Nucleic AcidsRNA structure - tRNA, hammerhead ribozyme, Tetrahymena groupI intron (catalytic)
Nucleotides & Nucleic AcidsChemistry - denaturation
High temp/pHNo covalent bonds broken
Normal temp/neutral pH
SLOW
QUICK
Normal temp/neutral pH
Nucleotides & Nucleic AcidsChemistry - denaturation
Lowest absorption of UV light
Lower absorption of UV lightthan free nucleotides
HYPOCHROMIC EFFECT -decrease in absorption as you go from free nt → single strands → doublestranded(can monitor transition from ds to ss)
Nucleotides & Nucleic AcidsBiosynthesis and Degradation
Biosynthesis:De novo pathways - uses metabolic precursors (AAs, ribose 5-phosphate, CO2, NH3)
Salvage pathways - recycle free bases and nucleosides releasedfrom nucleic acid breakdown
Nucleotides & Nucleic AcidsDegradation:
Deficiency in adenosine deaminase (causes ADA deficiency)Cannot break down adenosine, so it builds up, also [dATP] builds up
dATP is an inhibitor of ribonucleotide reductase, high [dATP] causesgeneral deficiency of other dNTPS in lymphocytes
Poor development of T and B lymphocytes, ineffective immune system
Leads to severe combined immunodeficiency syndrome (SCIDS), alsocalled “bubble boy” disease
First gene therapy for ADA
Elevated uric acid in bloodCaused by deficiency of one of purine metabolic enzymes
Causes gout
Uric acid causes inflammation of joints, problems in kidneys
Treatment = Drug allopurinol, which is an inhibitor of xanthineoxidase (enzyme that catalyzes step that makes uric acid)
Nucleotides & Nucleic AcidsChemotherapeutic drugsCancer cells grow rapidly, so they are in constant need of nucleotidesCancer cells more sensitive than normal cells to inhibitors of nucleotidebiosynthesis
Analogs of glutamine
Used in de novo synthesis