Biochemistry 2280A Lecture Notes - Lecture 4: Procollagen-Proline Dioxygenase, Hydroxylysine, Endoplasmic Reticulum
18 Jul 2016
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Biochemistry 2280 topic 4 protein functions and enzymes. Characteristics that allow proteins to function: flexibility and conformational changes. Driving force behind motor proteins: multitude of folding patterns, substrate specificity. Kd = dissociation constant: as kd increases, enzyme affinity increases. Family of fibrous, strong proteins; strength tissue membranes. Rich in glycine 1/3 of amino acid residues are glycine. Present prolines and lysines can be hydroxylated into hydroxylproline and hydroxylysine. Maturation and assembly into fibrils: individual polypeptides are around 1000 residues long, n- and c- terminal sequences of initial polypeptide removed later, chains hydroxylated in endoplasmic reticulum by two enzymes. Come together into more extended helical formation: hydroxylysines are sites for glycosylation (addition of sugars) to increase solubility and crosslinking between chains, trim off propeptide, procollagen now becomes tropocollagen, tropocollagen assembled into fibrils with covalent crosslinks. Different igg molecules have same overall structure but different antigen binding site (abs)
