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Q145 Poly-L-Iysine exists in pure α-helix, β-sheet and random coiled conformation depending upon the solvent conditions. Tile values of mean residue ellipticity at 220 nm ([θ]220) are -35,700, -13,800 and +3,900 deg cm2 dmol-1 for α-helix, β-sheet and random coil conformations of this polypeptide, respectively. The polypeptide exists in α- helix conformation at pH 10.8 and 250 C. Addition of urea leads to a two state transition between α-helix and random coil conformation. It has been observed that [θ]222 of the polypeptide is -14800 degcm2dmol-1in the presence of 6M urea. The percentage of the polypeptide in α-helix conformation is:

Options

Choose one · Correct answer highlighted

37 41 47 Correct 50

Explanation

q145 poly-l-iysine exists in pure α-helix, β-sheet operates via 47 represents established outcome. functional assays validates option C. Other options propose substrate or regulatory direction, inconsistent with published kinetics and mutant phenotypes.

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