BIOL-UA 21 Lecture Notes - Lecture 5: X-Ray Crystallography, Protein Folding, Alpha Helix
15 May 2016
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Document Summary
X-ray crystallography: send an x-ray beam through crystal (alignment of many instances of protein) reflection of x-ray beam in regular repeating pattern interpret pattern of dots to determine structure. Motif: more related to structure, not as much focused on function. Zinc finger motif: alpha helix and two beta strands. Zinc ions coordinated between two histamines and two cystines. Projects and fits inside groove of dna, touch/recognize particular bases. Breaking non-covalent interactions (denaturing) and then cool it back down, will fold back into same shape every time. Other proteins need help to get into minimum energy structure (native form. Could need chaperones every time, could be only after damage, etc. Proteins facing inside barrel of chaperone have hydrophobic residues exposed (hydrophobic needs to be on inside) Denatured protein enters barrel and meets hydrophobic residues on inside of barrel. Protein is teased apart free up hydrophobic residue to go back inside refold.
