BIOC 440 Lecture #3: Protein Structure I - Amino Acids: The Alphabet - Prof. Rachel Klevit, Study notes of Biochemistry

Download BIOC 440 Lecture #3: Protein Structure I - Amino Acids: The Alphabet - Prof. Rachel Klevit and more Study notes Biochemistry in PDF only on Docsity! 1 BIOC 440 Lecture #3 1 “Protein Structure I. Amino Acids: The Alphabet of Proteins” I. Structures & general properties II. Special properties • ASSIGNED READING: Chap. 3: p. 71-77, 79-81 • REVIEW READING: Sect 2.1 • Lehninger Web tutorial: see Web link listed on BIOC440 Schedule page. • REVIEW & TEST yourself online (use Web link listed on BIOC440 Schedule page.) • HOMEWORK PROBLEM SET #1 2 Introduction to Proteins • most DIVERSE class of biomolecules • perform an AMAZING array of functions: Structural Chemical Signalling Regulatory How do they do it??? 3 Amino acids are the monomeric building blocks of proteins • Amino acids are CHIRAL, therefore proteins have a “handedness.” 4 • all have ≥TWO ionizable groups AMINO group carboxylic ACID Fig. 3-10 • isoelectric point: 2 5 The “language” of proteins is based on a 20-letter alphabet…YOU must learn your “A, B, C’s”! For all 20 AAs, you must know: 1. Name 2. 3-letter code 3. 1-letter code 4. Structure of R group; type of functional group 5. Classification 6. Prevalent charged forms @ physiological pH 7. Important functional properties 6 Classification by side chain properties side chain = R group; attached to Cα. • 5 main classifications, based on POLARITY or tendency to interact with H2O at physiological pH. Non-polar aliphatic, Aromatic, Polar/uncharged, Positively charged, Negatively charged • SOLUBILITY depends on relative strength of: 7 • HYDROPHILIC: Solubility Properties of Biomolecules • HYDROPHOBIC: • AMPHIPHILIC: 8 Some Useful data on Amino Acids Table 3-1