Biochemistry I Spring/Summer 2024 Lecture 4 PDF

Biochemistry I Spring/Summer 2024 Lecture 4 March 19, 2024 Textbooks: Mark’s Basic Medical Biochemistry 5th Edition And Harper’s Illustrated Biochemistry 30th Edition Exam 1 Tuesday March 26 covering lectures 1-4, homework, reading Protein Structure http...

Biochemistry I Spring/Summer 2024 Lecture 4 March 19, 2024 Textbooks: Mark’s Basic Medical Biochemistry 5th Edition And Harper’s Illustrated Biochemistry 30th Edition Exam 1 Tuesday March 26 covering lectures 1-4, homework, reading Protein Structure https://www.amherst.edu/system/files/media/0438/Protein%252520Structure %252520F11.pdf lysine Salt bridge aspartate Other protein tertiary stabilization interactions in protein folding involve R groups. R groups participate in hydrogen bonding, electrostatic (ionic or salt Bridges), disulfide bonds (between cysteines), hydrophobic interactions. ser val Backbone val hydrogen bonding cys cys between peptide glu bonds in β sheets / α helix arg asp NAD+ Ribbon drawing showing the arrangement of secondary structures into a three- dimensional pattern in domain 1 of lactate dehydrogenase. The individual polypeptide strands in the six-stranded β- sheet are shown with arrows. Different strands are connected by helices and by nonrepetitive structures (turns, coils, and loops). This domain is the nucleotide- binding fold. Nicotinamide adenine dinucleotide (NAD+) is bound to a site created by the helices (upper left of figure, in green). Antiparallel Tendency: one face polar (hydrophilic). One face non polar (hydrophobic) Parallel Tendency: both faces hydrophobic. Globular Proteins: examples: hemoglobin and myoglobin Function: Function: Oxygen Oxygen transport storage in from lung to tissue, skeletal and CO2 transport to cardiac muscle lungs, buffer – absorb H+ α globin genes chromosome 16 β globin genes chromosome 11 RBC cannot synthesize globins since RBC they lack a nucleus RBC cannot synthesize heme since they lack mitochondria. ATP is supplied by anaerobic glycolysis- produce lactic acid Protoporphyrin IX Heme ferrous Adult hemoglobin: HbA: 2α and 2β chains α1 and β1– strong hydrophobic interactions between them α2 and β2 - strong hydrophobic interactions between them α1 β1 and α2β2 dimers have weak ionic salt bridges linking them that can be formed or broken proximal F8, His 93 Distal His Distal His E7, His 64 distal F8, His 93 Lung approx. 100 mmHg Tissue 26 mmHg Metabolically active tissue < 26 mmHg Myoglobin- releases oxygen < 5 mmHg Sigmoidal curve- due to cooperative binding P50 = partial pressure of oxygen at which 50% of hemoglobin or myoglobin is saturated P50 hemoglobin approx. 26 mmHg Metabolically active tissue releases CO2 and lactic acid HbO2 + H+ → HbH+ + O2