BIOC12H3 Lecture 7: BIOC12 Lecture 7.doc
21 Jul 2013
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Slide 2: collagen: connective tissue that plays a role in strength & flexibility. Dense extracellular matrix component: myoglobin & haemoglobin: not an enzyme, oxygen carrier. Each heme group contains one iron atom, an example of ligand binding. Each iron (part of the heme group) atom binds one oxygen molecule: antibodies. Binding of antigen at each end of the fork, which is then presented to phagocytic cell. Slide 3 collagen: a fibrous protein different from -keratin ( -helix) Procollagen refers to the one strand in tropocollagen (triple helix) 3 residues (amino acids) per turn, not as compacted, slightly extended than -helix (3. 6 residues (amino acids) per turn) Each of the three identical helix is left-handed, but the overall structure is a right-handed super- helix/ coil. Strength of collagen is due to covalent bonds: 1) covalent crosslink (between the three helices (strands)), ex. 2) covalent bonds within the strand (intramolecular bond), ex. bond between two allysines.
