Amino Acids and Proteins: Structure, Role, and Formation - Prof. C. Mallery, Lab Reports of Biology

Download Amino Acids and Proteins: Structure, Role, and Formation - Prof. C. Mallery and more Lab Reports Biology in PDF only on Docsity! amino acids & proteins Mallery 1 Bil 255 – CMB amino acids & their role in protein structure amino acids & proteins Mallery 2 Amino Acids & their role in Proteins… Proteins - the penultimate molecules ? structurally complex functionally sophisticated long repeats of individual monomers (amino acid’s) most abundant molecule in cells 15% of cell’s dry mass Amino Acids R H2N - C - COOH H 20 common amino acids - p74-75 panel 2.5 lys-arg-his-asp-glu-ala-val-leu-ile-pro-phe-met-trp-gly-cys-ser-thr-tyr k - r - h - d - e - a - v - l - i - p - f - m - w - g - c - s - t - y amino acids & proteins Mallery 5 classes of amino acids [classified... by R-Groups] AROMATIC (hydrophobic non-polars) PHE,MET,TRP,GLY,PRO,CYS contain R groups with ring structures & others NON-POLAR... (aliphatic) ALA, VAL, LEU, ILE, contain only hydrocarbons R groups = hydrophobicity POLAR UNCHARGED... SER, THR, TYR, ASN, GLN are soluble in water, i.e., hydrophilic BASIC... positively charged LYS, ARG, HIS R group with 2nd amide that protonates below pH 7.0 ACIDIC... negatively charged ASP & GLU R group with 2nd COOH that ionizes above pH 7.0 mcb 2.13* amino acids & proteins Mallery 6 Peptide Bond... formed by condensation reaction between amino of one aa... & carboxyl of another aa ... substituted amide covalent bond – dipeptide has partial double bond character – shorter & stronger than C-C longer, yet weaker than C=C no free rotation (group in same plane, but TRANS) results is zig-zag planar molecule figure* peptide bonds* & a polypeptide* amino acids & proteins Mallery 7 There are only 3 known ways to make a peptide bond... 1. chemical abiotic synthesis in the laboratory 2. genetic engineering cloning mechanisms 3. biologically in cells... (@25aa/sec in prokaryotic cells) Some common terminology: dipeptide, tripeptide, oligopeptide, polypeptide protein - polymer of a-L-amino acids joined by peptide bonds whale myoglobin - panel 4.2 pg 132-133