Biol. 1311 – 9/6/06 – Protein structure/function Most metabolic functions depends on protein structure 20 amino acids in an almost infinite number of possible sequences Linear sequence is a polypeptide; when folded into 3D shape it is a protein 20 amino acids to not memorize: (Fig 3.5) The peptide bond links amino acids head to tail (N to C) (3.9/10) The peptide bond limits rotation of atoms (not quite in Fig 3.9) Think about rigidity when considering flexibility (Fig. 3.11) Linear sequence is primary structure (fig 3.10b); Really no structure at all Folding gives actual structure: No eq. fig. Most protein structure is 2 o structure; Placement of 2 general types of local structures Alpha helix and (beta) pleated sheet Each is held together by hydrogen bonds between peptide backbone members Alpha helix/pleated sheet with no side groups shown (Fig. 3.14b) Placing secondary structures in space creates 3D shape Not much of protein is anything other than helix or sheet Problem is how is it decided what goes where? Side group interactions determine this
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This note was uploaded on 01/24/2010 for the course BIO 1311 taught by Professor Shinkle during the Fall '06 term at Trinity University.